For this case we propose a system of equations.
We know that a dime equals 10 cents and a nickel equals 5 cents.
So:
x: Let the variable that represents the number of dimes
y: Let the variable that represents the number of nickels
According to the statement we have:
We multiply the first equation by -0.10:
We have the following equivalent system:
We add the equations:
So, Jeff has 3 nickels
Jeff has 12 dimes.
Answer:
12 dimes and 3 nickels