Find The Next Number in the series:

12 13 15 17 111 113 117 119 123 ?

I am a white box having no key or lid.
Yet there is a golden treasure inside it.

What Am I?

Can you find out a way through which you can make five squares out of the given figure by moving just six match sticks?

Can you think of any three-dimensional shape that comprises of exactly two surfaces?

What will be the best approach to finding all the prime numbers less than 75 that leave an odd reminder when we divide them with 5?

What numbers should go on the bottom line?
3 6 9 15
8 2 10 12
11 8 19 27
19 10 29 39
? ? ? ?

You are playing a game with your friend Jack. There are digits from 1 to 9. You both will take turn erasing one digit and adding it to your score. The first one to score 15 points will win the game.

Would you want to play first or second?

PS: The sum should be exactly 15.

A man hijacks an aeroplane transporting both passengers(8 of them) and valuable cargo. After taking the cargo, the man demands nine parachutes, puts one of them on, and jumps, leaving the other eight behind. Why did he want eight?

I am weightless, but you can see me. Put me in a bucket, and I'll make it lighter. What am I?

Can you find the next number in the below sequence
3 , 7 , 10 , 11 , 12 , 17 ?