a woman swims downstream 54 km and upstream 6 km taking 6 hours each time , what is the speed of the woman in still water ?
"54 - - - 6 ds = 9 ? - - - - 1 6 - - - - 6 us = 1 ? - - - - 1 m = ? m = ( 9 + 1 ) / 2 = 5 answer : d"
divide(add(divide(54, 6), divide(6, 6)), const_2)