A man rows his boat 85 km downstream and 25 km upstream, taking 2 1/2 hours each time. Find the speed of the stream?  Choose the most appropriate option
A) 6	B) 12	C) 5	D) 8	E) 9
Speed downstream = d/t = 85/(2 1/2) = 34 kmph   Speed upstream = d/t = 25/(2 1/2) = 10 kmph   The speed of the stream = (34 - 10)/2= 
<gadget id="calculator">(34 - 10)/2</gadget>
<output>12</output>
12 kmph   Answer: 12
<result>B</result>
A man rows his boat 85 km downstream and 25 km upstream, taking 2 1/2 hours each time. Find the speed of the stream?