The speed of a boat in still water is 12 kmph. What is the speed of the stream if the boat can cover 32 km downstream or 16 km upstream in the same time?	Choose the correct answer.
A) 5 kmph B) 6 kmph C) 7 kmph D) 4 kmph E) 10 kmph
X = the speed of the stream   (12 + X) / (12 - X) = 2/1   12+ X = 24 - 2X   3X = 12   X = 4 km/hour   If the speed of the stream is 4km/hour, then the 'downstream' speed of the boat is   12+4= 
<gadget id="calculator">  12+4</gadget>
<output>16</output>
16km/hour and the 'upstream' speed of the boat is 12-4= 
<gadget id="calculator">12-4</gadget>
<output>8</output>
8km/hour. In that way, if the boat traveled for 2 hours, it would travel 2x8= 16km downstream and 2x16 = 32km/hour upstream.   Answer : 4 kmph
<result>D</result>
The speed of a boat in still water is 12 kmph. What is the speed of the stream if the boat can cover 32 km downstream or 16 km upstream in the same time?