13 decks of cards have been mixed. What is the minimum number of cards that must be taken out from the above-mixed cards to guarantee at least one 'four of a kind?

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?

In the picture given below, can you find out which digit will take place of the question mark?

During an experiment, a guy throws a bouncy ball from a 100 feet tall building. The ball has a specific characteristic. Every time it hits the ground, it bounces up halfway.

How many bounces do you think the ball will make before it comes to a stop ?

A bag contains 64 balls of eight different colours. There are eight of each colour (including red). What is the least number you would have to pick, without looking, to be sure of selecting 3 red balls?

The day after tomorrow will be three days before Tuesday. Can you find out what is today?

Complete the series by replacing "?" with the correct number.

ST ND RD TH '?'

If,

A + B = C
D - C = A
E - B = C

Based on the above equations, find out the answer for:

D + F = ?

Can you solve this amazing hard number series problem?
7, 8, 10, 12, 16, 18 ?

Three fair coins are tossed in the air and they land with heads up. Can you calculate the chances that when they are tossed again, two coins will again land with heads up?