SOLUTION: Sana is twice as old as her youngest brother. If the difference between their ages is 15 years. How old is her youngest brother?

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Question 912465: Sana is twice as old as her youngest brother. If the difference between their ages is 15 years. How old is her youngest brother?
Found 2 solutions by ewatrrr, battyb:
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
x youngest brother's age
(15-x) = 2x
15 = 3x
5 = x, youngest brother's age
And...checking (Sana's age 10)
10+=+2%2A5

Answer by battyb(1) About Me  (Show Source):
You can put this solution on YOUR website!
Sana is twice as old as her youngest brother:

s = 2b

If the difference between their ages is 15 years:

s = b + 15

Since we know the value of s is equal to 2b, we can substitute:

2b = b + 15

Then subtract b from each side:
2b = b + 15
-b   -b

b = 15

Therefore, the age of the little brother is 15 years.
And the age of Sana is 30.