a person can swim in still water at 16 km / h . if the speed of water 8 km / h , how many hours will the man take to swim back against the current for 12 km ?
"m = 16 s = 8 us = 16 - 8 = 8 d = 12 t = 12 / 8 = 1.5 answer : b"
divide(12, subtract(16, 8))