Question 828778: Mary is 2 times Tim's age. Tim is 5 more than Gina's age. Mary is 3 times Gina's age. How old are they altogether?
Answer by JulietG(1812)   (Show Source):
You can put this solution on YOUR website! Let M = Mary's age
Let T = Tim's age
Let G = Gina's age
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The question tells us the following:
M = 2T
T = G+5
M = 3G
or, M = 2T = 3G
Substitute the value for T
M = 2(G+5)
M = 2G + 10
Now substitute the value given for M
3G = 2G + 10
Subtract 2G from each side:
G = 10
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Now that we know Gina's age, we can plug the others in.
Mary is 3x Gina's age, or 30
Tim is 5 years older than Gina, or 15 (we can prove that by the other statement that Mary is twice Tim's age)
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Add them together:
Mary 30 + Tim 15 + Gina 10 = 55
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