SOLUTION: Have several problems like this one: (Need a formula) Mr. Merrill has 3 times as many nickels as dimes. The coins have a total value of $1.50. How many of each coin does he

Question 9352: Have several problems like this one: (Need a formula)
Mr. Merrill has 3 times as many nickels as dimes. The coins have a total value of $1.50. How many of each coin does he have? (I know the answer is 18 nickels and 6 dimes but it comes from experience of handling change in a store and I don't know how to arrive at a formula or equation.)
Answer by DWL(56) (Show Source): You can put this solution on YOUR website!
Let X = dimes
Let Y = Nickels
We know Y = 3X
We also know that .10 = Dimes and .05 = Nickles
So X+Y=1.50
We substitue the following:
.10X + 3(.05X)=1.50
.10X + .15X = 1.50
.25X = 1.50
Divide both sides by .25
X = 6 Dimes
So we know we have 3 times as many nickels as dimes, 6 x 3 = 18.
Answer:
6 dimes = .60
18 Nickels = .90
Total = 1.50
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