A boat goes 100 km downstream in 10 hours, and 75 m upstream in 15 hours. The speed of the stream is?	Choose the correct choice from the following answers:
A) 22 1/9 kmph  B) 22 8/2 kmph  C) 22 1/8 kmph  D) 22 1/2 kmph  E) 22 1/4 kmph
100 --- 10 22 1/2 kmphS = 10   ? ---- 1   75 ---- 15 US = 5   ? ----- 1 S = (10 - 5)/2   = 2 21/2 kmph   Answer:22 1/2 kmph
<result>D</result>
A boat goes 100 km downstream in 10 hours, and 75 m upstream in 15 hours. The speed of the stream is?