### Instruction: A certain barrel, which is a right circular cylinder, is filled to capacity with 300 gallons of oil. The first barrel is poured into a second barrel, also a right circular cylinder, which is empty. The second barrel is twice as tall as the first barrel and has twice the diameter of the first barrel. If all of the oil in the first barrel is poured into the second barrel, how much empty capacity, in gallons, is left in the second barrel?
Answer Choices: (A) There is no empty capacity (B) 2100 gallons (C) 2300 gallons (D) 2100 gallons (E) 2800 gallons.### Response: Let's think about the multi-choice question step by step.
Radius of first cylinder=r, diameter=2r, height=h
Radius of second cylinder=2r, diamter=2d and height=2h
Volume of first cylinder=pie (r^2)*h=300
Volume of second cylinder=pie(2r^2)2h
Put the value of pie (r^2)*h=300 in the second cylinder,volume= pie (r^2)*4*2=300*8=2400 gallons
Empty capacity=2100 gallons
The answer is D