A man can row his boat with the stream at 25 km/h and against the stream in 13 km/h. The man's rate is? Choose the correct choice from the following choices:
A) 1 kmph
B) 2 kmph
C) 6 kmph
D) 8 kmph
E) 3 kmph

Rationale: "ds = 25 us = 13 s = ? s = ( 25 - 13 ) / 2 = 6 kmph answer : c"
Answer: C