The speed at which a man can row a boat in still water is 15 kmph. If he rows downstream, where the speed of current is 3 kmph, what time will he take to cover 100 metres?  Pick: A) 22 seconds B) 65 seconds C) 78 seconds D) 20 seconds E) 21 seconds
Speed of the boat downstream   = 15 + 3= 
<gadget id="calculator">15 + 3</gadget>
<output>18</output>
18 kmph= 18 * 5/18= 
<gadget id="calculator">18 * 5/18</gadget>
<output>5</output>
5 m/s   Hence time taken to cover 60 m= 100/5= 
<gadget id="calculator">100/5</gadget>
<output>20</output>
20 seconds.   Answer:20 seconds
<result>D</result>
The speed at which a man can row a boat in still water is 15 kmph. If he rows downstream, where the speed of current is 3 kmph, what time will he take to cover 100 metres?