maths question help please!

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thescribe
Posts: 62
Joined: Tue Nov 18, 2014 10:05 am

maths question help please!

Post by thescribe »

Can someone help me with this problem please? I want to help my son, but I'm struggling with some of the questions myself! :shock: :shock:

Craig is arranging plates of food for a party.

He has 3 types of sandwich, 2 types of cake, and 4 types of biscuit.

Which shows the number of possible combination of sandwich, cake and biscuit on a plate?

1. (3x2) + (3x4)
2. 3 x 2 x 4
3. (3x4) + (2x4)
4. 3 + 2 + 4
5. (2x3) + (2x4)

Thank you!
Guest55
Posts: 16254
Joined: Mon Feb 12, 2007 2:21 pm

Re: maths question help please!

Post by Guest55 »

It's the second option ... take S as sandwich, C as cake and B as biscuit ...

S1 C1 B1
S1 C1 B2
S1 C1 B3
S1 C1 B4

now repeat for cake 2 etc
thescribe
Posts: 62
Joined: Tue Nov 18, 2014 10:05 am

Re: maths question help please!

Post by thescribe »

Thank you Guest!

Unfortunately it's still gibberish to me :-( I'm trying to figure it out but I just don't get it :-(
Tagore
Posts: 121
Joined: Thu Jun 14, 2012 10:28 am

Re: maths question help please!

Post by Tagore »

thescribe,
my dd had a difficulty understanding similar questions so I devised a way of explaining to her - this maybe frowned upon by teachers but it has worked for me.
You have 3 types of sandwich, 2 types of cake and 4 types of biscuit. First consider the sandwich and cake combination. Draw 3 circles vertically, representing the sandwiches, and then 2 circles adjacent to the 3 circles, representing the cakes. Now draw a line from each sandwich to each cake and you will find you have six combinations. Now draw six circles in a vertical line, representing the 6 combinations of cakes and sandwiches and 4 circles in a line adjacent to represent the biscuits. Now draw a line from each of your 6 combinations to each type of biscuit and you will find that you 24 combinations. Now find which of the answers gives you 24 combinations.

This is just a method to teach. With practice, children should be encouraged to appreciate that the number of combinations is simply a product of the types.

I hope this helps
Tagore
thescribe
Posts: 62
Joined: Tue Nov 18, 2014 10:05 am

Re: maths question help please!

Post by thescribe »

Tagore wrote:thescribe,
my dd had a difficulty understanding similar questions so I devised a way of explaining to her - this maybe frowned upon by teachers but it has worked for me.
You have 3 types of sandwich, 2 types of cake and 4 types of biscuit. First consider the sandwich and cake combination. Draw 3 circles vertically, representing the sandwiches, and then 2 circles adjacent to the 3 circles, representing the cakes. Now draw a line from each sandwich to each cake and you will find you have six combinations. Now draw six circles in a vertical line, representing the 6 combinations of cakes and sandwiches and 4 circles in a line adjacent to represent the biscuits. Now draw a line from each of your 6 combinations to each type of biscuit and you will find that you 24 combinations. Now find which of the answers gives you 24 combinations.

This is just a method to teach. With practice, children should be encouraged to appreciate that the number of combinations is simply a product of the types.

I hope this helps

Tagore

Thank you! That really helps and I get it now! :-) Honestly, I'm not usually this dim but I just couldn't get my head around it. Thank you both!
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