There are two tanks A & B with same capacity of 20 litres. If the water inflow rate (speed) in Tank A is 2 litres per hour & in Tank B is 4 litres per hour. How much longer tank A takes to fill than Tank B?	Select:  A) 4 hours  B) 5 hours  C) 3 hours  D) 2 hours  E) 1 hour

Rationale: time taken for tank a to fill = 20 / 2 = 10 hours time taken for tank b to fill = 20 / 4 = 5 hours so tank a takes 5 more hours to fill answer : b
Answer: B