Question 1129897: There were 30 nickels,dimes,and pennies, and their value was $1.35. If there were twice as many pennies as dimes, how many of each kind were there?
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! There were 30 nickels,dimes,and pennies, and their value was $1.35. If there were twice as many pennies as dimes, how many of each kind were there?
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Equations:
p + n + d = 30 coins
p + 5n + 10d = 135 cent
p = 2d
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Substitute for "p"::
n + 3d = 30
5n+12d = 135
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Modify and solve for "d"::
5n + 15d = 150
5n + 12d = 135
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Subtract and solve for "d"::
3d = 15
d = 5 (# of dimes)
p = 2d = 10 (# of pennies)
n + 3*5 = 30
n = 15 (# of nickels)
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Cheers,
Stan H.
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