Jump to content

Help with a Year 4 maths problem please
DH & I have several different answers


  • Please log in to reply
53 replies to this topic

#1 ~*Amethyst*~

Posted 11 February 2013 - 06:42 PM

Can anyone help in how to work out a 'Family Maths Question' please.

Family Maths Challenge 2

At your party you have decided to serve triple decker ice creams!
* There are 5 yummy flavours - peppermint, chocolate, strawberry, banana and tutti frutti.
  * How many combinations of three flavours could you create?
  * How many combinations of three flavours could you create if one flavour is always chocolate?
  * How many combinations all together (including 3 scoops the same, 2 the same and one different)?

XxxAmethyst


#2 secret~sammy

Posted 11 February 2013 - 06:49 PM

1) 5 chose 3 = 10

nCr = n! / (n - r)! r!

nCr = 5!/ (5 - 3)! 3!
nCr = 5!/ 2! 3!
nCr = (5 * 4 * 3 * 2 *1) / (2 * 1)(3 * 2 * 1)
nCr = 120 / (2 * 6)
nCr = 120 / 12
nCr = 10

2) 4 choose 2 (because 1 is always choc) = 6 by the formula above

3) 5^3 = 125

#3 Georgie01

Posted 11 February 2013 - 06:50 PM

QUOTE
How many combinations of three flavours could you create?


5x4x3=60 (you have 5 choices for the first flavour, then 4 for the second, 3 for the third since you aren't allowed to repeat any flavours)

QUOTE
* How many combinations of three flavours could you create if one flavour is always chocolate?


1x4x3=12 (1 choice is chocolate then 4 (all except chocolate) then 3 (not chocolate and not the second flavour)

QUOTE
How many combinations all together (including 3 scoops the same, 2 the same and one different)?


5x5x5=125 (because you can choose any of the five flavours for each scoop)

(hoping that I haven't done something wrong, seems to make sense original.gif )

#4 FeralCrazyMum

Posted 11 February 2013 - 06:51 PM

OMG I can't understand that formula ... it's not really a Year 4 question???
ETA: Georgie01, that answer makes more sense to me, still seems difficult for the age, but that could be because of my lack of maths skills.

Edited by CrazySingleMum, 11 February 2013 - 06:52 PM.


#5 Peppery

Posted 11 February 2013 - 06:54 PM

1. 15

2. 6

3. 125

Honestly these are guesses, my father was a mathematician (retired) would be absolutely horrified at my lack of mathematical reasoning

#6 Fright bat

Posted 11 February 2013 - 06:56 PM

Georgie's answer is correct.

I remember doing combinations in primary school.

#7 libbylu

Posted 11 February 2013 - 07:00 PM

Does the order of the flavours matter? If not, then the first poster is correct, if not, then the second poster is correct!
Does seem very complex for year 4.

#8 jayskette

Posted 11 February 2013 - 07:01 PM

1) 5*4*3
2) 4*3*2 - edited to say - oops... should be 4*3
3) 5*5*5

This is actually an extension maths question... unless the grade 4 people are smarter than when I did this as an extension when I was in year 4... lol

Try this one (another "extension" question on ratios that I actually got in year 4)

There is a piece of orchestral music that is played by 60 Strings, 60 Woodwind and 40 Brass, and it lasts 2 minutes 35 seconds.
How long will the music take to be played if it is played by 40 Strings, 30 Woodwind and 20 Brass?

ROFL

Edited by jayskette, 11 February 2013 - 07:03 PM.


#9 Georgie01

Posted 11 February 2013 - 07:05 PM

My grade 4 has done a little bit of this sort of thing - I work through it with him the way that I did here. It can help to use a diagram or find five different things an do a bit of a model to understand the reasoning.

I haven't had to use factorials with him as the worksheets ask him to explain how he thought things through and I'm fairly sure he hasn't learned factorials/combinations/permutations formally.

QUOTE
Does the order of the flavours matter? If not, then the first poster is correct, if not, then the second poster is correct!


Ahhh, thank you! I need to brush up.

Yes, my answers assume that choc/strawberry/banana is different to choc/banana/strawberry, Secret~Sammy's solution calls those the same...

Reading the question again Secret Sammy is right because the question asks for combinations so it's implied that the order doesn't matter and choc/strawberry/banana=strawberry/banana/choc etc.  Not sure how I'd help a year 4 work through that logically other than with a chart (assuming they haven't actually been taught the formula)

Edited by Georgie01, 11 February 2013 - 07:23 PM.


#10 Lagom

Posted 11 February 2013 - 07:06 PM

QUOTE (jayskette @ 11/02/2013, 08:01 PM) <{POST_SNAPBACK}>
There is a piece of orchestral music that is played by 60 Strings, 60 Woodwind and 40 Brass, and it lasts 2 minutes 35 seconds.
How long will the music take to be played if it is played by 40 Strings, 30 Woodwind and 20 Brass?


roll2.gif


Edited by amabanana, 11 February 2013 - 07:07 PM.


#11 secret~sammy

Posted 11 February 2013 - 07:10 PM

Whilst I still think I'm right  and the order of the flavours doesn't matter  cool.gif  -  Now that I think about it I suspect for a year 4 question the answer they are looking might be Georgie's one.

#12 secret~sammy

Posted 11 February 2013 - 07:13 PM

Whilst I still think I'm right  and the order of the flavours doesn't matter  cool.gif  -  Now that I think about it I suspect for a year 4 question the answer they are looking might be Georgie's one.

#13 ~*Amethyst*~

Posted 11 February 2013 - 07:14 PM

This was in DS homework book to be done tomorrow night as a family - no guidance - no instructions.

DH & I have spent the last 2 hours working on it & still aren't sure that we have calculated it correctly.

The answers are:

10

6

41

So it seems secret-Sammy was closest & Georgie's answer is incorrect?

How on earth are we supposed to explain this to our 9 year old & what is the purpose of such homework?

I find it very frustrating.

XxxAmethyst

#14 ~*Amethyst*~

Posted 11 February 2013 - 07:14 PM

This was in DS homework book to be done tomorrow night as a family - no guidance - no instructions.

DH & I have spent the last 2 hours working on it & still aren't sure that we have calculated it correctly.

The answers are:

10

6

41

So it seems secret-Sammy was closest & Georgie's answer is incorrect?

How on earth are we supposed to explain this to our 9 year old & what is the purpose of such homework?

I find it very frustrating.

XxxAmethyst

#15 CherrySunday

Posted 11 February 2013 - 07:24 PM

This is why I hated mathematics in primary school (and subsequently in secondary).

If you ever came across this in real life, would you care how many combinations you could make, or just be glad you could have 3 flavours of ice cream at once? Tounge1.gif

#16 PatG

Posted 11 February 2013 - 07:24 PM

Are you saying that the answers given are 10, 6 and 41?

If you are happy with 60 (5*4*3) as total permutations (order does matter) then try the following:

Each permutation of a, b, c can be written in 6 different ways (a, c, b etc).  Therefore to get the total combinations you need to divide 60 by 6 to get rid of the repeats, leaving 10.

Do the same with chocolate start - 1 x 4  x 3 = 12 , divide by 2 combinations of the second two scoops = 6

My solution to part c - total variations including multiple of the same flavour:

10 different ways to have 3 different flavours
5 different ways to have all the same flavour
20 ways to have 2 scoops the same and one diff  (4 different ways to have 2 scoops of chocolate and one other, multiply by the 5 flavours you could have two scoops of)

Total:  35.

I don't know what the other 6 are.....  The part b answer (6) is included in part a.

this webiste seems to agree with me 35 as an answer  I'm guessing I'm mis interpreting something

Edited by PatG, 11 February 2013 - 07:53 PM.


#17 FeralZombieMum

Posted 11 February 2013 - 07:30 PM

Ok I cheated and googled it.
http://www.docstoc.com/docs/134459705/Family-Maths-Challenge

There are 10 flavours of 3 combinations.
There are 6 combinations if one flavour is always chocolate.
There are 41 combinations altogether.


#18 ~*Amethyst*~

Posted 11 February 2013 - 07:30 PM

Yes PatG.  I got the second answer, DH the first & neither of us the last!

XxxAmethyst

#19 Lucrezia Borgia

Posted 11 February 2013 - 07:31 PM

The answer is 47


#20 Peppery

Posted 11 February 2013 - 07:32 PM

QUOTE (ZombieMum @ 11/02/2013, 08:30 PM) <{POST_SNAPBACK}>
Ok I cheated and googled it.
http://www.docstoc.com/docs/134459705/Family-Maths-Challenge

There are 10 flavours of 3 combinations.
There are 6 combinations if one flavour is always chocolate.
There are 41 combinations altogether.


Woohoo I got one right!!!!!!

#21 PatG

Posted 11 February 2013 - 07:35 PM

Sorry, have been adding to my prior post.... missed some of the updates.

#22 FeralZombieMum

Posted 11 February 2013 - 07:36 PM

The key word is combination.
QUOTE
Mathematicians eat ice cream just like anyone else.
But sometimes they take longer to make up their mind about what flavour of ice cream they would like to have, especially when they want a double scoop ice cream and there are 31 different flavours to choose from.
If I want a double scoop ice cream cone how many possible double scoop cones are there to choose from?

Now that’s a problem!!!


It has to do with things called  ‘COMBINATIONS’ and ‘PERMUTATIONS’.

If you think it doesn’t matter which flavour is on
top and which one is on the bottom,
then you are thinking about COMBINATIONS.


But if you think that a double scoop ice cream cone with strawberry on the top and lemon on the bottom is not the same as lemon on the top and strawberry on the bottom, then you are thinking about PERMUTATIONS.

There is a big difference.


#23 Georgie01

Posted 11 February 2013 - 07:43 PM

Oh, who knew there were solutions online! A couple of those maths challenges have taken us hours too.

What I will do when my year 4 comes home with that one is to sit down with 5 coloured textas and a big piece of paper and work through it.



#24 ~*Amethyst*~

Posted 11 February 2013 - 07:45 PM

I can't access that website on the iPad Zombiemum? It wants me to download something & then to enter my credit card details?

XxxAmethyst

#25 FeralZombieMum

Posted 11 February 2013 - 07:48 PM

It didn't explain it, just had the answers, so you don't need to view it online - plus you already knew the answers anyway. original.gif




1 user(s) are reading this topic

0 members, 1 guests, 0 anonymous users

 

Celeste Barber: the hilarious Aussie mum you must follow

If you have ever looked at a photo of a celebrity mum and felt a pang of despair then Celeste Barber is your new best friend.

18 tips for surviving the first few weeks with a newborn

Here are 18 tips I think would have helped me when I went into this whole parenting thing blind.

Share your baby's first taste photos to win

Heinz and Essential Baby are giving away $1000 and baby food hampers - enter today!

Thumb-suckers could have less allergies, study shows

Thumb-sucking and nail-biting might alter the immune system function.

The shocking statistic that shows pregnant women need more support

For women suffering from chronic morning sickness or hyperemesis gravidarum (HG), pregnancy is the roller coaster from hell.

Free ticket offer

Pinky Mckay joins us again at the Essential Baby & Toddler Show presented by Blackmores with her expert baby settling advice. Register now for your free ticket.

Dad-to-be plans big surprise for gender reveal party

But for one mum-to-be, the big announcement was mixed with another emotional moment, all planned by her partner.

I was a victim of narcissistic abuse - now I'm speaking out

I met a guy who immediately swept me off my feet. Fast forward five years and I'm sitting alone in a house, crying and pregnant.

Alanis Morissette welcomes baby girl

Alanis Morissette is sharing pictures of her baby girl on social media.

Enduring postnatal anxiety

My hopeless, paralysing love for my children wasn't useful; it wasn't practical. I wasn't in charge.

New mum shares photo of herself in a "giant diaper"

After giving birth, most mothers post a photo to social media.

The art of oral storytelling - and how you can start it with your kids

In this form of communication, the heart listens as well as the ears.

Healing after miscarriage: 6 ways to soften the grief

If you have suffered a pregnancy loss, here are six ways to help soften the grief.

Your handy guide to a mum's tired signs

From the minute that tiny babe is out of you, you'll start hearing about "tired signs".

Prince George checks out helicopters at air show

The Duke of Cambridge has shown his son the inner workings of a helicopter at the Royal International Air Tattoo at RAF Fairford.

Dad catches a Pokemon as his wife waits to give birth

An Aussie dad found himself capturing a Pokemon in a very unusual place: his wife's hospital bed as she waited to give birth.

Mum's warning on dangers of liquid detergent capsules after toddler's accident

A mum has taken to social media to warn others about the dangers of laundry liquid capsules after her daughter was left with serious burns in her eyes.

Mum left reeling over 'breastfeeding' toddler post

For so many little kids, breastfeeding is just something that mummies do.

Does cannabis affect a man's sperm?

If you're pregnant or planning to be, tobacco and alcohol are high on the list of things not to use.  But do we need an equally loud message about avoiding cannabis too?

 
Advertisement
 

Top 5 Articles

Advertisement
 
 
 

What's hot on EB

Why drinking water can be deadly for babies

H2O is one of the necessities of life, but for babies a seemingly harmless amount of water can be fatal.

5 ways having a baby is different when you have older children

So much parenting advice is geared towards having your first baby, but what's it like having a baby when you already have children?

You can now make your own plush Falkor

Fans of The NeverEnding Story – of which there are certainly plenty – went crazy for these plush Falkors when they first went on sale last year.

Baby steps

10 things that will actually happen after having a baby

I thought I had prepared myself for motherhood. Then my baby girl arrived and knocked everything flat.

Having a baby: expectations vs reality

People love to warn you about what to expect when having a baby, but they can be way off when it comes to the reality.

Are we having fun yet? Thinking positively as a parent

Motherhood is wonderful ... except when it sucks.

The adorable smile of a baby seeing his mum clearly for the first time

There is no doubt seeing their child smile for the first time is an unforgettable moment for parents everywhere.

When breastfeeding doesn't go with the flow

Breast is best, except when it's not. And in our case, it most definitely wasn't.

'If you don't vaccinate your kids you're a bloody idiot'

The photos are heartbreaking and almost too difficult to look at, but Kayley Burke is begging other parents to take notice.

Why pregnant women should eat chocolate

In news that will make expectant mums jump for joy - and reach for a block of Cadbury - scientists have revealed chocolate could provide health benefits during pregnancy.

The baby born with an incredible head of hair

If you're in any way challenged in the follicle department, prepare to feel a jolt of envy - at a two-month-old baby.

The push for Medicare to fund lactation consultants

While meeting with a lactation consultant can make an enormous difference to a new mother, it's not a service that is available through the public health system.

Parents, this is how to cut grapes to avoid choking

One mum has learnt a harrowing lesson about the best way to cut grapes to make it safe for toddlers and little kids to eat.

Three truths about C-section mums

Lately I've been thinking about the caesarean stories and the brave women who birth their children with strength and beauty.

Help! My baby will only sleep in my arms

It's stressful to be the one who is holding your baby most of the day, but it's even more stressful to wonder, 'am I doing something wrong? Or am I creating bad habits?'

 

ENTER NOW

Win $1000 with Heinz!

We want to see photos of your baby eating - and by sharing, you'll be in the draw to win $1000 and baby food hampers. Enter today!

 
Advertisement
 
 
Essential Baby and Essential Kids is the place to find parenting information and parenting support relating to conception, pregnancy, birth, babies, toddlers, kids, maternity, family budgeting, family travel, nutrition and wellbeing, family entertainment, kids entertainment, tips for the family home, child-friendly recipes and parenting. Try our pregnancy due date calculator to determine your due date, or our ovulation calculator to predict ovulation and your fertile period. Our pregnancy week by week guide shows your baby's stages of development. Access our very active mum's discussion groups in the Essential Baby forums or the Essential Kids forums to talk to mums about conception, pregnancy, birth, babies, toddlers, kids and parenting lifestyle. Essential Baby also offers a baby names database of more than 22,000 baby names, popular baby names, boys' names, girls' names and baby names advice in our baby names forum. Essential Kids features a range of free printable worksheets for kids from preschool years through to primary school years. For the latest baby clothes, maternity clothes, maternity accessories, toddler products, kids toys and kids clothing, breastfeeding and other parenting resources, check out Essential Baby and Essential Kids.