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