The speed at which a man can row a boat in still water is 21 kmph. If he rows downstream, where the speed of current is 5 kmph, what time will he take to cover 90 metres?  Options:
A) 23.46	B) 27.46	C) 28.46	D) 12.46	E) 25.46

Rationale: speed of the boat downstream = 21 + 5 = 26 kmph = 26 * 5 / 18 = 7.22 m / s hence time taken to cover 90 m = 90 / 7.22 = 12.46 seconds . answer : d
Answer: D