Note that 10 dimes make a dollar, and
4 quarters make a dollar
If Cooper has 4 dimes and 7 quarters, then his total amount of money is;
[tex]\begin{gathered} \text{Total}=4(0.1)+7(0.25) \\ \text{Total}=0.4+1.75 \\ \text{Total}=2.15 \\ \text{The total money he has is \$2.15} \end{gathered}[/tex]
(b) if he has x dimes and y quarters, then his total money would be;
[tex]\begin{gathered} \text{Total}=x(0.1)+y(0.25) \\ \text{Total}=0.1x+0.25y \end{gathered}[/tex]
