Let the number of coins = X
A nickel is 0.05
A dime is 0.10
A quarter is 0.25
Set up an equation to add all the coins together to equal the total she has:
0.05x + 0.10x + 0.25x = 2.00
Simplify:
0.40x = 2.00
Divide both sides by 0.40
x = 2.00 / 0.40
x = 5
Check:
Nickels = 0.50 x 5 = 0.25
Dimes = 0.10 x 5 = 0.50
Quarters = 0.25 x 5 = 1.25
0.25 + 0.50 + 1.25 = 2.00
She has 5 of each coin.