A man swims downstream 32 km and upstream 24 km taking 4 hours each time, what is the speed of the man in still water? Choose the correct option.
A) 9	B) 8	C) 6	D) 7	E) 2

Rationale: "32 - - - 4 ds = 8 ? - - - - 1 24 - - - - 4 us = 6 ? - - - - 1 m = ? m = ( 8 + 6 ) / 2 = 7 answer : d"
Answer: D