kwah wrote:Attached is a question from GMAT Prep Test #2.
What is the most efficient way of achieving the result?
Answer: B
Thanks,
K
(1) The amount of the bill was between $15 and $50 implies 15 < bill < 50.
If the bill = $20 then the tip = 2 * 2 = $4 (2 times tens digit) so more than 0.15 * 20 = $3 (15% of the bill)
If the bill = 29$ then the tip would still be 2 * 2 = $4 but here it is less than 0.15 * 29 = $4.5 approx.
No definite answer; NOT sufficient.
(2) The tip calculated by the martin was $8 implies 40 ≤ bill < 50
If the bill is exactly $50, 15% of $50 = 0.15 * 50 = $7.50, which is less than $8.
So the answer to the question is "yes"; SUFFICIENT.
The correct answer is
B.
