Question 972980: Nick has $7.70 in quarters and dimes, and the total number of coins is 38. How many quarters and how many dimes? Found 2 solutions by Boreal, macston:Answer by Boreal(15235) (Show Source):
You can put this solution on YOUR website! x=quarters
38-x= dimes
.25x + .10 *(38-x)=7.70 all units dollars and cents.
.25x + 3.80-.10x=7.70
.15 x =3.90
15 x=390
x=26
38-x =12
26 quarters ($6.50)
12 dimes ($1.20)
You can put this solution on YOUR website! Q=number of quarters; D=number of dimes
Q+D=38
D=38-Q Use this to substitute for D.
.
$0.25Q+$0.10D=$7.70 Substitute for D.
$0.25Q+$0.10(38-Q)=$7.70
$0.25Q+$3.80-$0.10Q=$7.70
$0.15Q=$3.90
Q=26 ANSWER 1: There are 26 quarters.
D=38-Q=38-26=12 ANSWER 2: There are 12 dimes
.
CHECK:
$0.25Q+$0.10D=$7.70
$0.25(26)+$0.10(12)=$7.70
$6.50+$1.20=$7.70
$7.70=$7.70
