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**ran****Member**- Registered: 2013-06-03
- Posts: 1

Hi hopefully you guys can help me with this problem sum.

there are 45 coins in the piggy bank.

total amount is $21.90

there are 7 $1 coins in the piggy bank.

how many $0.50 and $0.20 coins are there in the piggy bank?

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**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,395

hi ran,

Welcome to the forum.

I've made two equations from this information and tried to solve the problem. But the number of $0.50 coins has come out as a fraction so either I've made a silly error or the information has a typo. Have a look and see if you can sort it out; the method should work.

First some letters for the number of coins. I'm from the UK so I couldn't remember what you call those coins so for $0.50 I'm using H and for $0.20 I'm using F.

First equation based on number of coins

Second based on value of coins

Multiply the first by 2 and subtract the result from the second

Now if 73 was in the 3x table that would give H and F would quickly follow. But you cannot have H not a whole number so I'm stuck.

Bob

You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 86,776

Hi;

There are no integer solutions to that problem.

I think the problem is a typo. Now total amount is $21.80 has a solution.

**In mathematics, you don't understand things. You just get used to them.Of course that result can be rigorously obtained, but who cares?Combinatorics is Algebra and Algebra is Combinatorics.**

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