Calculate the number of urns of water needed to fill a tank of dimensions of 10x10x5m to 90% full, if the volume of the urn is 0.8m3 and can only be filled to 80%.  Answers: A) 520 B) 650.2 C) 685.5 D) 703.1 E) 712.2

Rationale: volume of the tank that needed to be filled = 10 x 10 x 5 x 0.9 = 450 volume of the urn that can be filled = 0.8 x 0.8 = 0.64 no . of urns of water needed to fill the tank = 450 / 0.64 = 703.1 answer : d
Answer: D