When n liters of fuel were added to a tank that was already 1 3 full, the tank was filled to 7 9 of its capacity. In terms of n, what is the capacity of the tank

Answer: 9/4n

Explanation:

Let's take T to represent tank

When n litres of fuel was added to tank that was 1/3 full = n + 1/3T

The tank was 7/9T

n+1/3T = 7/9T

n = 7/9T - 1/3T

n = 4/9

If a full tank is taken to be 1 = 9/9

Hence, we will have 1 = x * n

1 = x * 4/9

x = 9/4

Hence 9/4 of n = 9/4n