Given data:
The total numbers of nickel and dimes are n+d=19.
The expression for the total cost is 0.05n+0.1d=1.3.
The first equation can be written as,
[tex]n=19-d[/tex]Substitute above exprression in second equation.
[tex]\begin{gathered} \text{0}.05(19-d)+0.1d=1.3 \\ 0.95-0.05d+0.1d=1.3 \\ \text{0}.05d=0.35 \\ d=7 \end{gathered}[/tex]The numbers of nickels are,
[tex]\begin{gathered} n=19-7 \\ =12 \end{gathered}[/tex]Thus, the numbers of nickels are 12, and numbers of dimes are 7.
