The centre of the third figure is empty. What digit should fit inside?

What does this rebus means ?

PROG WORKRESS

Look at the below sequence of letters and tell us what the next letter should be:

O T T F F S S ?

What does below chemistry rebus means?

They do not possess flesh or feathers or scales or bone
But still, they are blessed with fingers and thumbs of their own.

Can you divide numbers from 1 to 9 (1 2 3 4 5 6 7 8 9) into two groups so that the sum of the numbers of each group is equal?

Note: 9 cannot be turned over to make it 6.

Make eight squares by moving only two matchsticks.
Note- Square can be of different sizes.

A pack of cards has 40 cards. You are blindfolded. Out of 40, 25 cards are facing down while 15 are facing up. You have been asked to divide this pack of cards into two decks - so that each deck contains an equal number of face-up cards. Remember, you are blindfolded.

How will you do it?

If Bihan is 10, Anirudha is 20, and Kim and Seal are both 5, but Rikold is 10, how much is Kenniger by the same trend?

What is the fastest way to double your money?