SOLUTION: rebecca donated 170 coins to pennies for Patients, all of which are nickels and dimes. The total value of her donation is $13.10. How much money did rebecca donate in just nickels?

Question 1066523: rebecca donated 170 coins to pennies for Patients, all of which are nickels and dimes. The total value of her donation is $13.10. How much money did rebecca donate in just nickels?
Answer by addingup(3677) (Show Source): You can put this solution on YOUR website!
n+d = 170 subtract n from both sides: d = 170-n
and
0.05n+0.10d = 13.10 substitute for d
0.05n+0.10(170-n) = 13.10
0.05n+17-0.10n = 13.10
-0.05n = -3.90
n = 78 Rebecca donated 78*0.05 = 3.90 in nickels
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Check:
nickels: 78 = $3.90
dimes: 170-78 = 92; 92*.10 = $9.20
total: 3.90+9.20 = 13.10 Correct.
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