GMAT- Prep: Bookseller

Vemuri wrote:Bookseller charges a Fixed Fee (FF) & an additional Shipping Fee (SF) for each book order. Its given that Rajeev placed orders for the following months:

Jan (1 book), Feb (2 books), Mar (3 books), Apr (4 books) & May (5 books).

So, the total fee is : (FF+SF) + 2(FF+SF) + 3(FF+SF) + 4(FF+SF) + 5(FF+SF)
==> 15(FF+SF)

Stmt1: The processing & Shipping fee was $1 more in March than in Jan. This statement does not give us any information on the individual expenses (processing & shipping fees) for each of the months. Insufficient.

Stmt2: 15SF = $7.5 ==> SF = $0.5. But, we have no information on the processing fee. So, this statement is not sufficient.

Combining both the statements, we still do not have information on the fixed fee component for each of the months.

Hence E

piyush_nitt wrote: As per my understanding ..

We need to calculate the value of 15(SF+FF)

SO 1st statement states that

3(FF+SF) - (FF+SF) = 1

FF+SF = 0.5

hence 15(SF+FF) = 7.5$

What I am missing here?

Vemuri wrote:

piyush_nitt wrote: As per my understanding ..

We need to calculate the value of 15(SF+FF)

SO 1st statement states that

3(FF+SF) - (FF+SF) = 1

FF+SF = 0.5

hence 15(SF+FF) = 7.5$

What I am missing here?

OK, my bad. Thanks for pointing out the flaw in my explanation.

The question stem says "The bookseller charges a Fixed processing fee and an additional Shipping fee for each book in the order".

So, for:
Jan - (FF+SF)
Feb - (FF + SF + SF) ==> FF+2SF
Mar - (FF + SF + SF + SF) ==> FF+3SF
Apr - (FF + SF + SF + SF + SF) ==> FF+4SF
Mar - (FF + SF + SF + SF + SF + SF) ==> FF+5SF

So, total = (FF+SF)+(FF+2SF)+(FF+3SF)+(FF+4SF)+(FF+5SF)
==> (5FF+15SF) ==> 5(FF+3SF)

Stmt1: The difference between Mar & Jan is $1.0, i.e. (FF+3SF) - (FF+SF) ==> 2SF = $1.0 ==> SF=$0.5. We do not know the value of FF to determine the total, so insufficient.

Stmt2: 15SF = $7.50 ==> SF = $0.5. Again we do not know the value of FF, so insufficient to find the total.

Together, the statements are not sufficient, hence E