Answer: 5 quarters
Work Shown
q = number of quarters
5q = number of nickels
0.25q = value, in dollars, of just the quarters
0.05*5q = 0.25q = value, in dollars, of just the nickels
0.25q+0.25q = 0.50q = value of all coins in dollars
0.50q = 2.50
q = 2.50/0.50
q = 5 is the number of quarters
5q = 5*5 = 25 is the number of nickels
Check:
5 quarters = 5*25 = 125 cents = $1.25
25 nickels = 25*5 = 125 cents = $1.25
$1.25 + $1.25 = $2.50
The answer is confirmed.