Find the next number in the sequence

5 12 24 36 ?

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 "P" means "-", "Q" means "/", "R" means "+", and "S" means "*" then find the value of the following:

21 Q 7 R 9 S 10 P 13

What can go up a chimney down, but can’t go down a chimney up?

In a school, there are four subjects. Seventy percent of students study English, seventy five percent of students study Science, eighty five percent of students study Mathematics and eighty percent of students study Spanish.

Can you calculate the percentage of students that study all four subjects?

Cristina was born in 1888. She just had her 30th birthday today how did that happen?

I am a mother. However, I never give birth.

I am a father. However, I never nurse my children.

Wandering is not possible for me, but standing still happens occurs rarely.

Who am I?

Do you know of a place where the wind blows south and then suddenly shifts direction towards the north?

I have a head like a cat and feet like a cat, but I am not a cat. What am I?

What four weights can be used to balance from 1 to 30 pounds?