SOLUTION: Mary is 16 years older than David, David is 13 years younger than Charlie. If the sum of their ages is 62, how old is Mary?

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Question 1155563: Mary is 16 years older than David, David is 13 years younger than Charlie. If the sum of their ages is 62, how old is Mary?
Found 2 solutions by greenestamps, MathTherapy:
Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


The given information compares Mary's and Charlie's ages to David's age. So use David's age as the variable:

x = David's age
x+16 = Mary's age (she is 16 years older than David)
x+13 = Charlie's age (David is 13 years younger than Charlie, so Charlie is 13 years older than David)

The sum of their ages is 62:

%28x%29%2B%28x%2B16%29%2B%28x%2B13%29+=+62

Solve using basic algebra.

Then remember the question asks for Mary's age, which is x+16 -- not just x.


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

Mary is 16 years older than David, David is 13 years younger than Charlie. If the sum of their ages is 62, how old is Mary?
Let Mary's age be M
Then David's is: M - 16, and Charlie's is: M - 16 + 13. or M - 3
Since all ages sum to 62, we get: M + M - 16 + M - 3 = 62
3M = 81
M, or Mary is: highlight_green%28matrix%281%2C4%2C+81%2F3%2C+%22=%22%2C+27%2C+years-old%29%29