The speed of a boat in still water is 18 kmph. What is the speed of the stream if the boat can cover 48 km downstream or 32 km upstream in the same time?	Select the correct option.
A) 4 kmph B) 5 kmph C) 6 kmph D) 7 kmph E) 8 kmph
X = the speed of the stream   (18 + X) / (18 - X) = 2/1   18+ X = 36 - 2X   3X = 18   X = 6 km/hour   If the speed of the stream is 6km/hour, then the 'downstream' speed of the boat is   18+6= 
<gadget id="calculator">  18+6</gadget>
<output>24</output>
24km/hour and the 'upstream' speed of the boat is 18-6= 
<gadget id="calculator">18-6</gadget>
<output>12</output>
12km/hour. In that way, if the boat traveled for 2 hours, it would travel 2x24= 48km downstream and 2x12 = 24km/hour upstream.   Answer : 6 kmph
<result>C</result>
The speed of a boat in still water is 18 kmph. What is the speed of the stream if the boat can cover 48 km downstream or 32 km upstream in the same time?