# Maths question that needs to explained to 10 year old

• Dec 29th 2008, 08:58 AM
dee@landspace.co.uk
Maths question that needs to explained to 10 year old
This is question which has to be explaine to a 10 year old.

6 lollies and 3 ice creams cost 8.52
3 icecreams and 6 drinks cost 9.24

How much does 1 lolly 1 ice cream and 1 drink cost?
Thanks

dee
• Dec 29th 2008, 09:05 AM
Chop Suey
Say you bought 6 lollies and 3 ice creams for 8.52 and 3 ice creams and 6 drinks for 9.24. You have bought a total of 6 lollies, 6 ice creams, and 6 drinks and you spent a total of 9.24+8.52=17.76.

We can then say that buying 6 lollies, 6 ice creams, and 6 drinks cost 17.76. If we divide by six, we can say that 1 lolly, 1 ice cream, and 1 drink cost 2.96
• Jan 1st 2009, 12:26 PM
janvdl
Quote:

Originally Posted by dee@landspace.co.uk
This is question which has to be explain to a 10 year old.

6 lollies and 3 ice creams cost 8.52
3 icecreams and 6 drinks cost 9.24

How much does 1 lolly 1 ice cream and 1 drink cost individually ?
Thanks

dee

Are you sure there is no other info? It won't be possible to determine the exact price of each, unless I'm missing something very simple.

This problem is very advanced for a 10 year old.

Let the lollies be \$\displaystyle x\$
The ice creams \$\displaystyle y\$
The drinks \$\displaystyle z\$

\$\displaystyle 6x + 3y = 8,52\$
\$\displaystyle 3y + 6z = 9,24\$

Divide both these equations by 3.

\$\displaystyle 2x + y = 2,84\$
\$\displaystyle y + 2z = 3,08\$

We can then simplify it to the following:

\$\displaystyle 2x + y - 2,84 = 0\$
\$\displaystyle y + 2z - 3,08 = 0\$

Therefore:

\$\displaystyle 2x + y - 2,84 = y + 2z - 3,08\$

This simplifies to:

\$\displaystyle x + 0,12 = z\$

Now we can try and get a general solution for it.

Let \$\displaystyle z = t\$

Then \$\displaystyle x = t - 0,12\$

And it follows that \$\displaystyle y = 3,08 - 2t\$
• Jan 1st 2009, 12:33 PM
skeeter
Quote:

Originally Posted by dee@landspace.co.uk
This is question which has to be explain to a 10 year old.

6 lollies and 3 ice creams cost 8.52
3 icecreams and 6 drinks cost 9.24

How much does 1 lolly 1 ice cream and 1 drink cost individually ?
Thanks

dee

recheck the problem statement. as stated by janvdl, one can't figure the individual cost for each item, but one can determine the total cost for one each of all three items ...

6 lollies and 3 ice creams cost 8.52
3 icecreams and 6 drinks cost 9.24

so ...

(6 lollies and 3 ice creams) + (3 ice creams and 6 drinks) cost (8.52 + 9.24)

6 lollies + 6 ice creams + 6 drinks cost 17.76

divide by 6 ...

1 lolli + 1 ice cream + 1 drink cost 2.96
• Jan 2nd 2009, 02:54 AM
dee@landspace.co.uk
Apologies to you guys. I have looked at the question again as per your advice and you are right. I did not read the question. They wanted the price for 1 lolly,1 Icecream and 1 Drink in total.

Sorry guys - Skeeter and Janvdl

Thanks

Dee
• Jan 2nd 2009, 02:58 AM
janvdl
Quote:

Originally Posted by dee@landspace.co.uk
Apologies to you guys. I have looked at the question again as per your advice and you are right. I did not read the question. They wanted the price for 1 lolly,1 Icecream and 1 Drink in total.

Sorry guys - Skeeter and Janvdl

Thanks

Dee

No worries :D