SOLUTION: Marta has $1.70 in quarters and dimes. She has 8 coins altogether. How many coins of each kind does she have?

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Question 957237: Marta has $1.70 in quarters and dimes. She has 8 coins altogether. How many coins of each kind does she have?
Answer by checkley77(12844) About Me  (Show Source):
You can put this solution on YOUR website!
Q+D=8 OR Q=8-D
.25Q+.10D=1.70
.25(8-D)+.10D=1.70
2.00-.25D+.10D=1.70
-.15D=1.70-2.00
-.15D=-.30
D=-.30/-.15
D=2 DIMES.
Q+2=8
Q=6 QUARTERS.
PROOF:
.25*6+2*.10=1.70
1.50+.20=1.70
1.70=1.70