Question 558028: Hanna has $11.20 in a jar that contains only nickels and dimes. There are 140 coins in the jar. How many dimes are in Hanna's jar?
Answer by saifoo.khan(162)   (Show Source):
You can put this solution on YOUR website! Hi,
:
Let n be the number of nickels, and d be the number of dimes.
From the first sentence:
(1) .05n + .10d = 11.2
Second sentence:
(2) n + d = 140
:
From equation 2, we subtract n from both sides:
(3) d = 140 - n
:
Substitute (3) into (1):
.05n + .1 (140 -n) =11.2
.05n + 14 - .1n = 11.2
-.05n = -2.8 (Multiply by -20 on both sides)
n = 56
:
Using equation #3:
d = 140 - 56
d = 84
:
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Cheers/
Saifoo.khan
einstein.saifoo@gmail.com
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