When a water tank is $30/%$ full, it contains 27 gallons less than when it is $20/%$ empty. How many gallons of water does the tank hold when it is full?

54 gallons

Step-by-step explanation:

Let x represent the volume of the full tank.

When the water tank is 30% full;

= 30% of x = 0.30x

when it is 20% empty:

= x - 20% of x = x - 0.20x = 0.80x

The difference is given as 27.

So, we can represent the question on an equation as;

0.80x - 0.30x = 27

Solving the equation, we have;

0.50x = 27

x = 27/0.50

x = 54 gallons

The tank can hold 54 gallons when it is full.