Question

Every evening Jenna empties her pockets and puts her change in a jar. At the end of the week she counts her money. One week she had 38 coins, all of them dimes and quarters. When she added them up, she had a total of $6.95. how many coins did jenna have

Answer 1

D + q = 38......d = 38 - q
0.10d + 0.25q = 6.95

0.10(38 - q) + 0.25q = 6.95
3.80 - 0.10q + 0.25q = 6.95
-0.10q + 0.25q = 6.95 - 3.80
0.15q = 3.15
q = 3.15 / 0.15
q = 21 <== number of quarters

d + q = 38
d + 21 = 38
d = 38 - 21
d = 17 <== number of dimes