When my father was 31 I was 8. Now he is twice as old as me. How old am I?

Count the squares in the matchstick puzzle below?

What kind of tree can you carry in your hand?

There are three boxes which are labeled as Rs100, Rs150, and Rs200. One box contains two notes of Rs. 50. The second box contains one note of Rs50 and one note of Rs100 The third box contains two Rs. 100 notes. All boxes are labeled incorrectly.

What is the minimum number of boxes you must check in order to label all boxes correctly?

How will you measure 15 minutes using two hourglasses of 7 minutes and 11 minutes respectively?

In the given figure, move three matchsticks so that the resulting figure contains two rectangles.

A famous swimmer can swim downstream in a lake in exactly 40 minutes with the lake current.
He can swim upstream in that lake in exactly 60 minutes against the lake current.
The length of the lake is 2 km.

How long he can cover the distance of one side at a still lake with no current?

Chocolate costs 6 rupees and a Toy costs 5 rupees. If you have 32 rupees in total, how many chocolates and how many Toys can be purchased with that amount?

In four steps you need to move the word 'cold' From 'warm' by replacing one alphabet at a time such that every word formed at each step is acceptable in English Dictionary.

What is the largest amount of money that you can possess in change and still if someone asks you for a dollar, you won't be able to give?