SOLUTION: mary has six dollars in quarters,dimes and nickels.She has three times as many dimes as nickels and 17 quarters. how many nickels and how many dimes does she have.

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Question 134957: mary has six dollars in quarters,dimes and nickels.She has three times as many dimes as nickels and 17 quarters. how many nickels and how many dimes does she have.
Answer by solver91311(12126) About Me  (Show Source):
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Since you are given that she has 17 quarters, you know that she has 17%2A.25=4.25 in quarters. Since she has a total of $6, you know that she has 6-4.25=1.75 in dimes and nickels.

Let the number of dimes be d and the number of nickels be n.

Then you are given that d=3n.

We also know that the value of d dimes is .10d, and the value of n nickels is .05n -- 10 cents per dime, and 5 cents per nickel.

The total value of her dimes and nickels is therefore .10d + .05n and we know this to be equal to $1.75.

.10d%2B.05n=1.75

But remember, d=3n, so:

.10%283n%29%2B.05n=1.75

.3n%2B0.5n=1.75

.35n=1.75

n=5

So she has 5 nickels and 3 * 5 = 15 dimes.

Check:
5 nickels = .25
15 dimes = 1.50
17 quarters = 4.25
4.25 + 1.50 + .25 = 6.00