Question

John has a total of 13 coins in his pocket. Of the 13 coins, they are all either quarters or dimes. The total value of the coins is $2.50. How many dimes does John have in his pocket?

Answer 1

5 dimes

Answer 2

put x = number of quarters and therefore 13-x is number of dimes solve
\[25x+10(13-x)=250\] for x

Answer 3

\[25x+130-10x=250\]
\[15x+130=250\]
\[15x=120\]
\[x=8\] so 8 quarters. the rest are dimes

Answer 4

If the following equation is used, then no follow on subtraction is required.
\[(13-x)(.25) +(x)(.10)=2.50\]