OG Wanda's telephone call

Hi AbeNeedsAnswers,

We're told that Wanda's telephone call was rounded up to the nearest whole minute by her telephone company. We're asked for the number of minutes that she was charged for her telephone call. We can answer this question with a bit of logic and TESTing VALUES.

1) The total charge for Wanda's telephone call was $6.50.

With Fact 1, we know the total cost of the call, but we don't know what rate Wanda was charged per minute.
Fact 1 is INSUFFICIENT

2) Wanda was charged $0.50 more for the first minute of the telephone call than for each minute after the first.

Fact 2 tells us the DIFFERENCE in the rates, but does not tells us the rates themselves nor the length of the call
Fact 2 is INSUFFICIENT

Combined, we know
-The total cost of the call was $6.50
-The first minute cost $0.50 more than each of the additional minutes

IF....
1st minute = $1.00 and each addl. minute = $0.50, then the call would have been 12 minutes
1st minute = $1.50 and each addl. minute = $1.00, then the call would have been 6 minutes
Combined, INSUFFICIENT

Final Answer: E

GMAT assassins aren't born, they're made,
Rich