Can you find out what is missing?

1 3 5
2 4 ?

Hint: It's not six. Think out of the box.

Which tank will fill first?

Can you find out the smallest number that can be conveyed as the sum of three squares in three unique ways?

Which number should replace the question mark?

What is the next number in the series?

15 29 56 108 208 ?

If,
29 - 1 = 30
9 - 1 = 10
14 - 1 = 15

Based on similar logic, Can you prove that the below algebraic equation is true?
11 - 1 = 10 ?

I have a hole in my back and legs I lack.
I live where I can’t breathe and I eat without teeth.
What am I?

A container contains 100 eggs. They can be either fresh or rotten. What is sure is the fact that there is at least one fresh egg in that container.

If you are asked to pick two eggs randomly from the container, at least one of them will be rotten.

Can you calculate how many eggs in that container are fresh?

A network of 20 x 10 squares is given to you.

Can you calculate how many unique squares and rectangles can be formed combining two or more individual squares ?

A couple went on a climbing trip. But only the husband returned from the vacation and said that his wife slipped off while climbing and died. On investigating, the local sheriff arrested him saying, 'Your travel agent called. You murdered your wife.'

The man did not inform anyone about the trip. Then how was the agent so sure that it was a murder?