SOLUTION: A boy is two years younger than his sister. Three years ago, the sum of their ages was 48. What is the boy's age?

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Question 1137518: A boy is two years younger than his sister. Three years ago, the sum of their ages was 48. What is the boy's age?
Found 3 solutions by greenestamps, josgarithmetic, MathTherapy:
Answer by greenestamps(13200) About Me  (Show Source):
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The difference in their ages will always be 2 years.

If the sum of their ages 3 years ago was 48, the sum of their ages now is 48+2(3) = 54.

If the sum of their ages is 54 and the boy is 2 years younger than his sister, simple logical reasoning tells us the boy is 26 and his sister is 28.

Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
x-2 and x
boy and sister

%28%28x-2%29-3%29%2B%28x-3%29=48
-
x-5%2Bx-3=48
2x=48%2B8
2x=56
x=28--------sister

x-2=highlight_green%2826%29------------"boy"

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

A boy is two years younger than his sister. Three years ago, the sum of their ages was 48. What is the boy's age?
Let boy's age be B
Then sister's age is B + 2
Since their ages summed to 48, 3 years ago, their ages sum to 48 + 6, or 54, now
We then get: B + B + 2 = 54
2B = 52
Boy's age, or highlight_green%28matrix%281%2C5%2C+B%2C+%22=%22%2C+52%2F2%2C+%22=%22%2C+26%29%29