If 21x = 79x, what is the value of x?

What does this mathematical rebus means ?

Why do you find that most of the buildings are deprived of the 13th floor?

What does below Rebus say?

XLR8

Two in a corner, one in a room, zero in a house, but one in a shelter. What am I?

I have Rs.50 and I spend it in the way as below.

You are confined in a room and given two metal rods. Out of these two rods, one is magnet and the other is the iron rod. They look starkly similar. You don't have any other metal object in the room.

How will you decide which one of those is magnet?

Speaking of rivers, a man calls his dog from the opposite side of the river. The dog crosses the river without getting wet, and without using a bridge or boat. How?

Given below is simple addition with a defined pattern pattern:
7 + 7 = 2
8 + 8 = 4
8 + 5 = 1
6 + 9 = 3
10 + 11 = 9

Can you analyze the pattern and find out the answer for:

4 + 9 = ?

If Rajina's daughter is my daughter's mom, who am I to Rajina?