SOLUTION: All together, 3 people have 120 coins. Mark has 3 times as many as Joel, and Joel has 1/2 as many as Sandra. How many coins does Sandra have?

Question 975051: All together, 3 people have 120 coins. Mark has 3 times as many as Joel, and Joel has 1/2 as many as Sandra. How many coins does Sandra have?

Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
All together, 3 people have 120 coins. Mark has 3 times as many as Joel, and Joel has 1/2 as many as Sandra. How many coins does Sandra have?
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Equations:
m + j + s = 120 coins
m = 3j
j = (1/2)s
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Substitute for s and m and solve for "j":
3j + j + 2j = 120
6j = 120
j = 20 coins (# of coins joel has)
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Now, solve for "s":
s = 2j
s = 40 coins (# of coins Sandra has)
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Cheers,
Stan H.
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