a man can swim in still water at 3 km / h , but takes twice as long to swim upstream than downstream . the speed of the stream is ?
"m = 3 s = x ds = 3 + x us = 3 + x 3 + x = ( 3 - x ) 2 3 + x = 6 - 2 x 3 x = 3 x = 1 answer : e"
divide(3, const_3)