A man can row a boat at 10 kmph in still water and the speed of the stream is 8 kmph. What is then time taken to row a distance of 90 km down the stream ?	Options
A) 8hrs  B) 5 hrs  C) 15 hrs  D) 15 hrs  E) 20 hrs
Speed in down stream = 10 +8= 
<gadget id="calculator">10 +8</gadget>
<output>18</output>
18   Time taken to cover 90 km down stream= 90/18= 
<gadget id="calculator">90/18</gadget>
<output>5</output>
5 hrs.   ANSWER:5 hrs
<result>B</result>
A man can row a boat at 10 kmph in still water and the speed of the stream is 8 kmph. What is then time taken to row a distance of 90 km down the stream ?