Question 65380
Let the number of dimes = d
Let the number of quarters = 2d-10
Let the number of half dollars = 2d-8

.10(d) + .25(2d-10) + .50(2d-8) = 4.70
.10d + .5d-2.5 + 1d-4 = 4.70
1.6d - 6.5 = 4.70
1.6d = 4.70+6.5
1.6d = 11.20
d=7

The number of dimes = 7
The number of quarters = 2(7)-10, which is equal to 4
The number of half dollars = 2(7)-8, which is equal to 6