Need a thorough explanation for this toughie

[ssgmatter]

A saleswoman's monthly income has two components, a fixed component of
$1000, and a variable component, which is $C for each set of encyclopaedias
that she sells in that month over a sales target of n sets, where n > 1. How
much did she earn in March?
(1) If she had sold three fewer sets than she actually did, her March income
would have been $600 less.
(2) If she had sold 8 sets of encyclopaedias, her income in March would
have been over $4000.

[albatross86]

I've trolled other forums about this question and everyone seems to find it weird. Here's how to approach it anyhow:

Fixed component = 1000
If x > n, Variable component = C (x - n) Where x is the number of sets she sells
Total income = 1000 + C(x - n)

If x < n, Variable component = 0


1. If x --> x - 3, Total income would have been 600$ less

i.e. 1000 + C(x - 3 -n) = 1000 + C (x - n) - 600
=> 3*C = 600
=> C = 200
Can we find "x" ? No. INSUFF

2. If x = 8, Total income > 4000$

i.e. 1000 + C(8 - n) > 4000
=> C(8 - n) > 3000
That doesn't really help us much does it? --> INSUFF


Both 1 and 2:

We have : 200 ( 8 - n) > 3000
=> 8 - n > 15
=> n < -7 , which is absurd, leading me to believe this question might be inherently flawed.

However, being as it is, I'd go with E.

[Stuart@KaplanGMAT]

Both 1 and 2:

We have : 200 ( 8 - n) > 3000
=> 8 - n > 15
=> n < -7 , which is absurd, leading me to believe this question might be inherently flawed.

Statements (1) and (2) contradict each other, which make this an impossible question (i.e. the answer isn't "E", it's "this question would never show up on the GMAT because it's flawed).

What's the source? You should always provide the source when you post a question.