A man can swim in still water at 1.5 km/h, but takes twice as long to swim upstream than downstream. The speed of the stream is? Pick one:
A) 1.7	B) 0.5	C) 1.1	D) 1.5	E) 1.9

Rationale: "m = 1.5 s = x ds = 1.5 + x us = 1.5 + x 1.5 + x = ( 1.5 - x ) 2 1.5 + x = 3 - 2 x 3 x = 1.5 x = 0.5 answer : b"
Answer: B