After 50 litres of petrol was poured into an empty storage tank, it was still 10% empty.
Total capacity of the tank ?

Correct option is A

Given:

Petrol poured = 50 litres

Tank is 10% empty 

90% filled

Formula Used:

Total capacity  = $$\dfrac{\text{Petrol poured}}{\text{Fraction filled}}$$​

Solution:
Total capacity $$=\frac{50}{0.90} =55.56\ \text{litres}$$​​