Qn. “A mother sent her boy to the river and told him to bring back exactly 7 pints of water. She gave him a 3-pint vessel and a 5-pint vessel. Show me how the boy can measure out exactly 7 pints of water, using nothing but these two vessels and not guessing at the amount. You should begin by filling the 5-pint vessel first. Remember, you have a 3-pint vessel and a 5-pint vessel and you must bring back exactly 7 pints.”
Ans. Fill the 5-pint vessel first. Pour the water into the 3-pint vessel. This leaves the first vessel with 2-pint of water. Pour the water in the 3-pint vessel back into the river. Pour the 2 pints of water from the first vessel into the second vessel. Now fill-in the first vessel fully. This will make the first vessel with 5 pints of water and the second vessel with 2 pints of water. Thus the solution.