SOLUTION: if i have 20 coins all dimes and quarters and total is $2.90 cent. How many of each coin do i have

Question 216619: if i have 20 coins all dimes and quarters and total is $2.90 cent. How many of each coin do i have

Answer by RAY100(1637) (Show Source): You can put this solution on YOUR website!
Let d = # dimes,,,,,,,,,and q= # quarters
.
(1) d + q = 20,,,,or q=20-d
.
(2) .1d +.25q = 2.90,,,,,,,,amt of money
.
subst (1) into (2)
.
.1d +.25(20-d) = 2.90
.
.1d -.25d +5 = 2.90
.
-.15 d = - 2.10
.
d=14,,,,,,,,,and q=20-d = 6
.
.
check,,,.1(14) + .25(6) = 1.40 + 1.50 = 2.90,,,,,ok
.

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