A boat goes 100 km downstream in 10 hours, and 75 Km upstream in 25 hours. The speed of the stream is? Pick.
A) 22 1/9	B) 6	C) 5	D) 3.5	E) 4.5
100 --- 10 DS = 10   ? ---- 1   75 ---- 25 US = 3   ? ----- 1 S = (10 - 3)/2= 
<gadget id="calculator">(10 - 3)/2</gadget>
<output>7/2 = around 3.5</output>
3.5 kmph.   Answer:3.5
<result>D</result>
A boat goes 100 km downstream in 10 hours, and 75 Km upstream in 25 hours. The speed of the stream is?