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

Why do we preferably have round manhole covers and not square ones?

What has a bottom at the top?

In a classic wine shop, the list of three most popular wines are:
- The cost of 1 French wine bottle: 500$
- The cost of 1 German wine bottle: 100$
- The cost of 20 Dutch wine bottles: 100$

John entered the wine shop and he needs to buy
- All three types of wine bottles.
- Needs to buy Dutch wine bottles in multiples of 20.
- Need to buy 100 wine bottles in total.

John has only 10000$. How many wine bottles of each type, John must buy?

I have Rs.50 and I spend it in the way as below.

Can you discover the missing number in this series?

37, 10, 82
29, 11, 47
96, 15, 87
42, ?, 15

You have two buckets of 11 liters and 6 litres.
How can you measure exactly 8 litres?

Can you find out which number multiplied by itself will give the output as 12345678987654321?

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

PS: You may start the number from 0.

I never was there, I am always to be.
You have never ever seen me, not ever you will.
Yet I am the confidence of everyone.

Who Am I?