Question 186830: Joe has a collection of nickels and dimes that is worth $6.05. If the number of dimes was doubled and the number of nickels was decreased by 10, the value of the coins would be $9.85. How many dimes does he have?
Answer by feliz1965(151)   (Show Source):
You can put this solution on YOUR website! n + d = 6.05......... Equation A
(n - 10) + 2d = 9.85...Equation B
Solve for n in Equation A.
n = 6.05 - d
We plug that value for n into Equation B.
6.05 - d + 2d = 9.85
6.05 + d = 9.85
d = 9.85 - 6.05
d = 3.80....This is the total value of the dimes Joe has. However and as you know, each dime is 10 cents.
How many dimes are in $3.80? There are 38 dimes.
To find the value of n, we select EITHER Equation A or B, plug 3.80 for d and simplify to find n. If you look carefully, you will notice that Equation A is easier to use.
I will use Equation A.
n + d = 6.05...Equation A
n + 3.80 = 6.05
n = 6.05 - 3.80
n = 2.25
How many nickels in $2.25?
Joe has 45 nickels.
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