Volume question?

Question

The indicator of an oil tank shows 1/5 full. After a truck delivers 165 gallons of oil, the indicator shows 4/5 full. What is the capacity (in gallons) of the tank?

Answer 1

Let x be the capacity of the tank.

From the given data 165 + (1/5)x = (4/5)x.

165 = (4/5)x - (1/5)x

165 = x[ 4/5 - 1/5]

165 = x(4 - 1)/5

165 = x(3/5)

⇒ x = (165 * 5)/3

= 55 * 5

= 275.

The capacity of the tank is 275 gallons.