Find the missing letter in the last circle logically in the given below picture.

Considering the below equation:

V + II - VI = 10
IV - X + VIII = 20
IV - VII + VI = 30

Then, I + II + III = ?

Look at this sequence from top to bottom. What is the next number in the sequence?
1
11
21
1211
111221
312211

A rubber ball keeps on bouncing back to 2/3 of the height from which it is dropped. Can you calculate the fraction of its original height that the ball will bounce after it is dropped and it has bounced four times without any hindrance ?

Can you think of a smallest +ve number such that if we shuffle the digits of the number, the new number becomes double the original number?

What can you see in the middle of March and April that you can never see in any other month?

A girl rode into a tourist spot out of the city on Thursday. She loved the place and decided to stay for a few days. She stayed for four days and then she left for back home on Thursday.

How can this be possible?

If you were to put a coin into an empty bottle and then insert a cork into the neck, how could you remove the coin without taking out the cork or breaking the bottle?

Can you find out the missing number?

? 4 5 3 5

9 5 7 10 3

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