a man ' s speed with the current is 21 km / hr and the speed of the current is 2.5 km / hr . the man ' s speed against the current is ?
"man ' s speed with the current = 21 km / hr = > speed of the man + speed of the current = 21 km / hr speed of the current is 2.5 km / hr hence , speed of the man = 21 - 2.5 = 18.5 km / hr man ' s speed against the current = speed of the man - speed of the current = 18.5 - 2.5 = 16 km / hr answer is c ."
subtract(subtract(21, 2.5), 2.5)