A man can row his boat with the stream at 10 km/h and against the stream in 6 km/h. The man's rate is?  Select
A) 2 kmph	B) 7 kmph	C) 98 kmph	D) 6 kmph	E) 4 kmph

Rationale: "ds = 10 us = 6 s = ? s = ( 10 - 6 ) / 2 = 2 kmph answer : a"
Answer: A