Look at the below sequence of letters and tell us what the next letter should be:

O T T F F S S ?

John was working on a Chemical Mixture whose weight comprise 90% liquid and 10% solid. The total weight of the mixture is 20 pounds. After a while, John noticed that some of the liquid evaporated and now the liquid comprises just 50% of the weight.

What is the weight of the chemical mixture now?

Below the four parts have been reorganised. The four partitions are exactly the same in both arrangements. Why is there a hole?

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?

If you go to the movies and you're paying, is it cheaper to take one friend to the movies twice, or two friends to the movies at the same time?

what does the below math rebus puzzle mean?

It belongs to you, but other people use it more than you do. What is it?

A pond had 60 fish, out of which, all but 20 died.
How many fishes are now present in that pond?

Why is the Hole below a Lock?

In the following picture, E is going to slide the object down and as per the terrain and the physics, the round object is going to travel all the way till the end. Now, can you analyze who all people will die when it happens?