Can you name some countries which do not have the alphabet 'A' in them?

An American nightclub called 'The Coconut Grove' had a terrible fire in which over 400 people died. A simple design flaw in the building led to a high death toll. Subsequently, regulations were changed to ensure that all public buildings throughout the country eliminated this one detail, which proved deadly. What was it?

Can you name four days which start with the letter 'T'?

What is harder to catch the faster you run?

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?

There are 3 apples in the basket and you take away 2. How many apples do you have now?

If a wheel has 54 spokes, how many spaces are there between the spokes?

The following alphametic has only one solution. Can you find it?
ENLIST + SILENT + LISTEN = ANAGRAM

PS: You may start the number from 0.

Why Aeroplane windows are round?

Solve the below puzzle by replacing the question mark with the correct number.

3 6 12

4 8 16

5 10 ?