Question

Which equation below could be used to solve the following problems? Karlie has a

collection of quarters, dimes, and nickles that equal $2.70. If she has 7 quarters and 7
nickles, how many dimes (d) does she have?
A. 0.10d + 7(0.25) + 7(0.5) = 2.70 ; d = -25.5
B. 0.10d + 7(0.25) + 0.05 = 2.70 ; d = 9
C. 10d +7(25 + 5) = 2.70 ; d = 20
D. 0.10d + 7(0.25 + 0.05) = 2.70 ; d = 6

Answer 1

Explanation:

0.25×7+0.05×7+0.10d=2.70

7(0.25+0.05)+0.10d=2.70

7(0.30)+0.10d=2.70

2.10+0.10d=2.70

0.10d=2.70-2.10

0.10d=0.60

d=0.60/0.10=6

Hence D