Question 199903
A collection of 43 coins consists of dimes and quarters. The total value is $7.60. How many dimes and how many quarters are there?
.
Let d = number of dimes
then
43-d = number of quarters
.
then
.10d + .25(43-d) = 7.60
.10d +  10.75 - .25d = 7.60
10.75 - .15d = 7.60
-.15d = -3.15
d = 21 (dimes)
.
quarters:
43-d = 43-21 = 22 (quarters)