Mo2men wrote:Pam gets on an elevator at the 12th floor of a building going up to the 70th floor. Hilary gets on the elevator on the 63rd floor at the same time in the same building going down to the 1st floor. At what floor will their paths cross?
(1) Pam's elevator is moving twice the rate of Hilary's elevator.
(2) Hilary's elevator is moving at a rate of 4 floors per second.
The problem should indicate that the floors are equally spaced and that the two elevators move at constant speeds.
Number of floors between Hilary and Pam = (Hilary's floor) - (Pam's floor) = 63-12 = 51.
Since Pam and Hilary are moving toward each other, they are WORKING TOGETHER to cover the 51 floors between them.
Statement 1: Pam's elevator is moving twice the rate of Hilary's elevator.
Implication:
Of every 3 floors between Pam and Hilary, Pam travels 2 floors, while Hilary travels 1 floor, with the result that Pam travel 2/3 of the 51 floors between her and Hilary.
Since Pam begins on the 12th floor, we get:
(12th floor) + (2/3)(51) = 12 + 34 = 46th floor.
SUFFICIENT.
Statement 2: Hilary's elevator is moving at a rate of 4 floors per second.
Without information about the speed of Pam's elevator, we cannot determine at what floor Hilary's elevator will pass Pam's elevator.
INSUFFICIENT.
The correct answer is
A.
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