SOLUTION: The total age of three sisters is 79. The youngest is 7 years younger than the middle. The age of the older is twice that of the youngest. What is the age of the middle?

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Question 1151808: The total age of three sisters is 79. The youngest is 7 years younger than the middle. The age of the older is twice that of the youngest. What is the age of the middle?
Found 2 solutions by josgarithmetic, MathTherapy:
Answer by josgarithmetic(39618) About Me  (Show Source):
You can put this solution on YOUR website!
Several problems like this have already been solved. Try giving a variable to "the middle" sister, and see what you can do literally with the description.

Answer by MathTherapy(10552) About Me  (Show Source):
You can put this solution on YOUR website!

The total age of three sisters is 79. The youngest is 7 years younger than the middle. The age of the older is twice that of the youngest. What is the age of the middle?
Let middle sister's age be M
Then the youngest's is: M - 7, and the oldest's is: 2(M - 7) = 2M - 14
The following SUM of AGES equation is formed: M + M - 7 + 2M - 14 = 79
Solve that for M, the middle sister's age.