Bunuel wrote:

If James is currently 1/3 as old as his mother, how old is James?

(1) In 10 years, James will be half as old as his mother will be then.

(2) James is now twice as old as he was 5 years ago.

We can let James’ current age = j and James’ mother's current age = m.

We have the following equation:

j = (1/3)m

3j = m

Statement One Alone:

In 10 years, James will be half as old as his mother will be then.

In 10 years, James will be (j + 10) and his mother will be (m + 10). The relationship between those two ages is that James will be ½ his mother’s age. We can create the following equation:

j + 10 = (m + 10)(1/2)

2j + 20 = m + 10

2j + 10 = m

Since 3j = m:

2j + 10 = 3j

j = 10

Statement one is sufficient to answer the question.

Statement Two Alone:

James is now twice as old as he was 5 years ago.

We can create the following equation:

j = 2(j - 5)

j = 2j - 10

j = 10

Statement two is sufficient to answer the question.

Answer: D

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Jeffery Miller

Head of GMAT Instruction

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