A boat goes 130 km downstream in 10 hours, and 75 Km upstream in 15 hours. The speed of the stream is?  Choose one:	A) 3.5	B) 3	C) 5	D) 4	E) 8

Rationale: "125 - - - 10 ds = 130 ? - - - - 1 75 - - - - 15 us = 5 ? - - - - - 1 s = ( 13 - 5 ) / 2 = 4 kmph . answer : d"
Answer: D