SOLUTION: Tim has twice as much money in nickels as in dimes. He has 30 coins in all. How many of each coin does he have?

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Question 1092835: Tim has twice as much money in nickels as in dimes. He has 30 coins in all. How many of each coin does he have?

Found 3 solutions by JoelSchwartz, ikleyn, greenestamps:
Answer by JoelSchwartz(130)   (Show Source):
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x=the number of nickels
y=the number of dimes
.05x=2(.1y)
.05x=.2y
x+y=30
x=30-y
.05(30-y)=.2y
1.5-.05y=.2y
1.5=.25y
6=y
x=30-6
x=24

Answer by ikleyn(52792)   (Show Source):
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.

Let N be the number of nickels. Then the number of dimes is (30-N). Amount of money (cents) in nickels is 5*N. Amount of money (cents) in dimes is 10*(30-N). The condition says 5N = 2*(10*(30-N)). It is your equation to solve. Simplify and find N: 5N = 20*(30-N) ====> 5N = 600 - 20N ====> 5N + 20N = 600 ====> 25N = 600 ====> N = = 24. Answer. 24 nickels and 6 = 30-24 dimes. Check Amount in nickels = 5*24 = 120 cents. Amount in dimes = 10*6 = 60 cents. ! Correct !.

Answer by greenestamps(13200)   (Show Source):
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Since the amount of money he has in nickels is twice the amount he has in dimes, and since each nickel is worth only half as much as each dime, we can deduce that the number of nickels he has is 4 times the number of dimes.

Then, since there are 30 coins in all, if we call the number of dimes d then

So he has 6 dimes and 24 nickels.