Prove that the below maths equation is true.

8 + 8 = 91

You are playing as white and given four rooks to checkmate the black king in four moves with the following rules 1. You can place one rook every move and ensure the black king should be in check position.2. After four moves the black king should be in the checkmate position.

Decode below rebus
D
N
A
T
S , D

Can you find out the number that should replace the question mark with a valid reason?

The below given figure comprises of a pattern through which you can determine the missing letter. Can you push your mind to find the pattern and add the missing letter?

In The Image Below Which clock is the odd one out?

Christina, Allison and Lena are 3 daughters of John a well-known Mathematician, When I asked John the age of their daughters. He replied "The current age of her daughters is prime. Also, the difference between their ages is also prime."

How old are the daughters?

A famous swimmer can swim downstream in a lake in exactly 40 minutes with the lake current.
He can swim upstream in that lake in exactly 60 minutes against the lake current.
The length of the lake is 2 km.

How long he can cover the distance of one side at a still lake with no current?

Can You Find the Missing Zero? A Number Puzzle that Will Trick Your Eyes

Anabelle is a clever trader of rare artefacts. Each day she carries three boxes each filled with thirty artifacts. The boxes can't hold more than that. She travels far in northern lands to sell these artefacts but on the way, she comes across thirty checkpoints where she has to shed one of the artefacts for each sack to the authorities for letting her pass.

How many artifacts will be left with her when she reaches her destination crossing all the checkpoints?