Since he has the same number of nickels as dimes.
x = nickels
x = dimes
500 - 2x = quarters
the total value of the coins is $72.50
5x + 10x + 25(500-2x) = 7250
Solve for x
15x + 25(500) + 25(-2x) = 7250
15x + 12,500 - 50x = 7250
Combine like terms
15x - 50x = 7250 - 12500
-35x = -5250
Divide both sides of the equation by -35
-35x/-35 = -5250/-35
x = 150
150 quarters