One-fourth of a tank holds 135 litres of water. What part of the tank is full if it contains 180 litres of water?
Options:
(A) 1/2
(B) 1/3
(C) 1/5
(D) 1/6
(E) 1/4 OK. Let's think. Some random thoughts first:
135 litres = 1/4 of tank
180 litres = 1/4 x 180/135 = 1/3 The answer: (B).