SOLUTION: Suppose that Maria has 150 coins consisting of pennies, nickels, and dimes. The number of nickels she has is 9 less than twice the number of pennies; the number of dimes she has is

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Question 646190: Suppose that Maria has 150 coins consisting of pennies, nickels, and dimes. The number of nickels she has is 9 less than twice the number of pennies; the number of dimes she has is 21 less than three times the number of pennies. How many coins of each kind does she have?
Answer by stanbon(75887) About Me  (Show Source):
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Suppose that Maria has 150 coins consisting of pennies, nickels, and dimes. The number of nickels she has is 9 less than twice the number of pennies; the number of dimes she has is 21 less than three times the number of pennies. How many coins of each kind does she have?
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Equations:
p + n + d = 150
n = 2p - 9
d = 3p - 21
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Substitute for "n" and for "d" and solve for "p":
p + 2p-9 + 3p-21 = 150
6p = 180
p = 30 (# of pennies)
n = 2p-9 = 51 (# of nickels)
d = 3p-21 = 69 (# of dimes)
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Cheers,
Stan H.
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