Ozlemg wrote:How am I going to understand whether the question stem asks the exact amount save in week 2, or the cummulated amount of W1 and W2? This point confused me!

As the question is asking "how much did he save in week 2", we have to find the exact amount he saved in week 2. If it had asked "how much did he saved till week 2" or something like that we had to find the total amount saved in week 1 and week 2.

If Jim saved a total of $90 in 3 weeks, how much did he save in week 2?

1. Jim's average savings for the first 2 weeks were $20
2. Jim's first week's savings were half of his savings in week 2 and a third of his savings in week 3

Statement 1: Total saving in first two weeks = $(2*20) = $40
But we cannot determine how much he saved in week 2.

Not sufficient

Statement 2: Say, he saved $x in week 1.
Therefore, he saved $2x in week 2 and $3x in week 3.

Thus, (x + 2x + 3x) = 90 ----> 6x = 90 ----> 2x = 30
So, he saved $30 in week 2.

Sufficient

The correct answer is B.