Which number should replace the question mark?

If you drop a 15 kg iron bar and a 5 kg bag of cotton from a height of 50 meters which will reach the ground first?

I have branches, but no fruit, trunk or leaves. What am I?

A 52% bias toss for head using the 51% tail bias coin was done to obtain a fair result.

Can you find how bias is the floor in this case?

Why is the Hole below a Lock?

You see a boat filled with people, yet there isn’t a single person on board. How is that possible?

Which word is least like the others? Third, fourth, fifth, sixth, seventh, eighth, ninth?

Can you find a pattern and the missing number in the series given below?

100, 155, 258,? , 584, 819.

In a university, a professor gave a set of three problems to the three brilliant students of his class. See the image for the questions.

Two men are in a desert. They both have packs on. One of the guys is dead. The guy alive has his pack open, and the guy who is dead has his pack closed. What is in the pack?