Louis has three more quarters than dimes in his pocket, for a total of $1.80. which of the following equation could be used to determine the number of dimes, x, in his pocket? .
a. 0.10(x+3)+0.25x=$1.80.
b. 0.10x+0.25(x+3)=$1.80.
c. 0.10(3x)+0.25x=$1.80.
d. 0.10x+0.25(3x)=$1.80

Number of dimes: x
Number of quarters:  x + 3

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)