John his wife and their daughter wish to cross a river The row boat can only hold 100kgs John weighs 80kgs and his wife and daughter weigh 40kgs each?

i don't get this question...unless it's a joke but the boat wouldn't be able to hold all of them, according to their weight as you said 100=40+40=900 How is that the answer its simply no they can not because John's 80kg + his wife's 40kg = 120kg + his daughters 40kg = 160kg they mother and daughter would need to go then John