an woman swims downstream 64 km and upstream 24 km taking 8 hours each time ; what is the speed of the current ?
"64 - - - 8 ds = 8 ? - - - - 1 24 - - - - 8 us = 3 ? - - - - 1 s = ? s = ( 8 - 3 ) / 2 = 2.5 answer : e"
divide(subtract(divide(64, 8), divide(24, 8)), const_2)