Bunuel wrote:
m and n are both positive. Pump A pumps n liters of water per minute, and pump B pumps m liters of water per minute. Is m < n ?
(1) x is the number of minutes it takes pump B to fill a 100 liter container alone, and 3x is the number of minutes it takes pump B to fill a 100 liter container while pump A pumps water out of that container.
(2) It takes (3x/2) minutes for pump A to fill a 100 liter container alone.
Project DS Butler Data Sufficiency (DS3)
For DS butler Questions Click Here Statement 1:Pick some numbers: x = 10
Situation 1: Pump B needs 10 minutes to pump 100 liters --> 10 l/min = n
Situation 2: Pump B needs 30 minutes (3x) to pump 100 liters, while Pump A pumps water out of the container --> rate of B is \(3\frac{1}{3}\) l/min
As the regular rate of Pump B is 10 l/min, Pump A has to pump out \(7\frac{2}{3}\) l/min so that the Rate of Pump B in Situation 2 becomes \(3\frac{1}{3}\) l/min
\(7\frac{2}{3}\) l/min > \(3\frac{1}{3}\) l/min
Rate of Pump A > Rate of Pump B
n > m
SUFF
Statement 2:Work = Rate * Time
100 L = n * \(\frac{3x}{2}\)
This statement tells us nothing about Pump B.
Additionally, we have two variables and one equation, which we can't solve.
NOT SUFF
Therefore
Answer A