The speed of a boat in still water is 20 km/hr and the rate of current is 5 km/hr. The distance travelled downstream in 12 minutes is:  Choose the correct choice from the following options.
A) 9  B) 5  C) 7  D) 6  E) 51

Rationale: "explanation : speed downstream = ( 20 + 5 ) kmph = 25 kmph distance travelled = ( 25 * ( 12 / 60 ) ) km = 5 km . answer : b"
Answer: B