a man swims downstream 48 km and upstream 42 km taking 6 hours each time ; what is the speed of the current ?
"explanation : 48 - - - 6 ds = 8 ? - - - - 1 42 - - - - 6 us = 7 ? - - - - 1 s = ? s = ( 8 - 7 ) / 2 = 0.5 answer : option b"
divide(add(divide(42, 6), divide(48, 6)), const_2)