Can you replace the question mark with the correct number?

Is the statement valid that it does not matter how much older a sibling is, eventually the younger one will be half as old as the older one?

Which is heavier: a ton of bricks or a ton of feathers?

Find the next number in the series below

21 32 54 87 131 ?

You have a 12 liters jug full of water. You have two empty 8 liters and 5 liters jug. How can you divide the water into two equal parts using these jugs?

Two batsman each on 94 runs. Seven runs needed to win in last 3 balls. Both make 100*. How?

P is the father of Q and S is the son of R. T is the brother of P and has a daughter U. If R is the sister of P, then what is the relation between U, Q and S?

John buys rice at Rs.60/kg from Britain and then sells them at Rs.5/kg in India. As a result of this, he becomes a millionaire. How come?

A prisoner is told: "If you tell a lie, we will hang you and if you tell the truth, we will shoot you." What did the prisoner say to save himself?

Write the next letter in this sequence.
O, T, T, F, F, S, S, E, __
**Hint: It is a Number Series Puzzle