12 buckets of water fill a tank when the capacity of each bucket is 81 litres. How many buckets will be needed to fill the same tank, if the capacity of each bucket is 9 litres? Choices.
A) 96  B) 110  C) 100  D) 90  E) 108

Rationale: "capacity of the tank = ( 12 ã — 81 ) litre number of buckets required of capacity of each bucket is 17 litre = 12 ã — 81 / 9 = 12 ã — 9 = 108 answer is e"
Answer: E