a person can swim in still water at 12 km / h . if the speed of water 2 km / h , how many hours will the man take to swim back against the current for 10 km ?
"m = 12 s = 2 us = 12 - 2 = 10 d = 10 t = 10 / 10 = 1 answer : a"
divide(10, subtract(12, 2))