SOLUTION: A purse containing $3.20 in quarters and dimes has, in all 20 coins. Find the number of each kind of coin.

Algebra ->  Customizable Word Problem Solvers  -> Coins -> SOLUTION: A purse containing $3.20 in quarters and dimes has, in all 20 coins. Find the number of each kind of coin.       Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 227261: A purse containing $3.20 in quarters and dimes has, in all 20 coins. Find the number of each kind of coin.
Answer by checkley77(12844) About Me  (Show Source):
You can put this solution on YOUR website!
Q+D=20 Q=20-D
.25Q+.10D=3.20
.25(20-D)+.10D=3.20
5-.25D+.10D=3.20
-.15D=3.20-5
-.15D=-1.80
D=-1.80/-.15
D=12 DIMES ANS.
Q=20-12=8 QUARTERS ANS.
PROOF:
.25*8=.10*12=3.20
2+1.20=3.20
3.20=3.20