A boat goes 100 km downstream in 10 hours, and 45 m upstream in 15 hours. The speed of the stream is?  Pick.
A) 22 1/7	B) 22 1/4	C) 3 1/2	D) 22 1/1	E) 22 1/3
100 --- 10 DS = 10   ? ---- 1   45 ---- 15 US = 3   ? ----- 1 S = (10 - 3)/2   = 3 1/2 kmp Answer: 3 1/2
<result>C</result>
A boat goes 100 km downstream in 10 hours, and 45 m upstream in 15 hours. The speed of the stream is?