Question

Solve the empty gas tank of a truck needs to be completely filled. the tank is shaped like a cylinder that is 3.5 ft long with a diameter of 2.2 ft . suppose gas is poured into the tank at a rate of 2.5 ft3 per minute. how many minutes does it take to fill the empty tank

Answer 1

5.3 minutes.  
First, let's calculate the volume of the tank. That will be the area of the base multiplied by it's length. And since it's base is a circle, the area is pi*r^2. So:
 V = l*pi*r^2
 V = 3.5 * pi * (2.2/2)^2
 V = 3.5 * pi * (1.1)^2
 V = 3.5 * pi * 1.21
 V = 4.235 * pi
 V = 13.30464489
 
 So the tank has a volume of about 13.3 ft^3. Now simply divide that volume
by the rate of incoming fluid. So
 13.3 / 2.5 = 5.32 
 Rounding to 2 significant figures gives a time of 5.3 minutes.