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) 2 (1/9) km/h  B) 2 (1/5) km/h  C) 2 (3/2) km/h  D) 2 (1/2) km/h  E) 2 (1/1) km/h
:100 --- 10 2 (1/2) km/hS = 10   ? ---- 1   75 ---- 15 US = 5   ? ----- 1 S = (10 - 5)/2   = 2 2 ½ kmph   Answer: 2 (1/2) km/h
<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?