A 300-Gallon Tank Is Full of a Solution Containing 35 $Q = e ^ { ( 1 / 30 ) t }$

Multiple Choice

A 300-gallon tank is full of a solution containing 35 pounds of concentrate. Starting at time distilled water is added to the tank at a rate of 30 gallons per minute, and the well-stirred Solution is withdrawn at the same rate. Find the amount of concentrate Q in the solution as a function Of t.

A) $Q = e ^ { ( 1 / 30 ) t }$
B) $Q = 30 e ^ { - ( 1 / 10 ) t }$
C) $Q = 300 e ^ { - ( 1 / 10 ) z }$
D) $Q = 35 e ^ { - ( 1 / 10 ) t }$
E) $Q = e ^ { - ( 1 / 35 ) z }$