a man swims downstream 36 km and upstream 48 km taking 6 hours each time , what is the speed of the man in still water ?
"36 - - - 6 ds = 6 ? - - - - 1 48 - - - - 6 us = 8 ? - - - - 1 m = ? m = ( 6 + 8 ) / 2 = 7 answer : c"
divide(add(divide(48, 6), divide(36, 6)), const_2)