Louis has three more quarters than dimes in his pocket, for a total of $1.80. Which equation could be used to determine the number of dimes, x, in his pocket?

Number of dimes: x

Number of quarters: x + 3

Answer:

B) 0.10 x + 0.25 (x + 3) = $1.80

Also we can solve this equation:

0.10 x + 0.25 x + 0.75 = 1.80

0.35 x = 1.80 - 0.75

0.35 x = 1.05

x = 1.05 : 0.35

x = 3, x + 3 = 6

He has 6 quarters and 3 dimes.

(6 * 0.25 + 3 * 0.10 = 1.50 + 0.30 = $1.80 - correct)