Question

the coins in the store's cash register total $4.00 the cash register contains only nickles dimes and quarters there is an equal number of each coin. how many dimes are in each cash register?

Answer 1

Say
\(x\)=number of quarters
\(y\)=number of dimes
\(z\)=number of nickles

Then, you can set your equation to be
\(4.00=0.25x+0.10y+0.05z\), you want the total amount of coins to be $4.00

But, you know that the number of coins is the same, so \(x=y=z\)
Thus you get now:
\(4.00=0.25x+0.10x+0.05x\)
\(4.00=0.40x\)
\(x=\frac{4.00}{0.40}=10\)
So, you have 10 coins of each type (quarter, dime, nickle)