Question

A coin bank has 250 coins, dimes and quarters, worth $39.25. How many dimes are in the coin bank? Write and solve a system of equations.

Answer 1

let x be the dimes and y the quarters. So we get

`\begin{gathered} \begin{cases}x+y=250 \\ 0.1x+0.25y=39.25\end{cases}\rightarrow x=250-y\rightarrow \\ 0.1(250-y)+0.25y=39.25 \\ 25-0.1y+0.25y=39.25 \\ 25+0.15y=39.25 \\ 0.15y=14.25 \\ y=(14.25)/(0.15)=95 \end{gathered}`

having that there are 95 quarters. We get that:

`x=250-95=155`

there are 155 dimes