There are people and strange monkeys on this island, and you can not tell who is who (Edit: until you understand what they said - see below). They speak either only the truth or only lies.
Who are the following two guys?
A: B is a lying monkey. I am human.
B: A is telling the truth.

Can you arrange four 9's and use at most 2 math symbols, to make the total 100?

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?

A finger goes in me. You fiddle with me when you're bored. The best man always has me first. What am I?

It's a 7-letter word.
If we remove 1 letter from it, it remains the same.
If we remove 2 letters from it, it remains the same.
If we remove 3 letters from it, it remains the same.
If we remove all the letters from it, still it remains the same.
What is it?

If,
9 * 8 * 7 = 65
8 * 7 * 6 = 50
7 * 6 * 5 = 37

Find
6 * 5 * 4 = ?

Solve the equation by replacing the alphabet with numbers.

MOM + MOM + NO = BOOK=

The doctor advised his patient to take a tablet after every fifteen minutes. He gave him five tablets in total.

How much time will he take to have all the five tablets?

Three doctors said that Bill was their brother. Bill says he has no brothers. How many brothers does Bill actually have?

On rolling two dices (six-sided normal dice) together, what is the probability that the first one comes up with a 2 and the second one comes up with a 5?