Can you write down eight eights so that they add up to one thousand?

I am a five-letter word and people eat me. If you remove the first letter I become an energy form. If you remove the first two letters, I am needed to live. Scramble the last three letters and I am a drink. What word am I?

You bought me for dinner but never eat me. What am I?

You are in a room that has three switches and a closed door. The switches control three light bulbs on the other side of the door. Once you open the door, you may never touch the switches again. How can you definitively tell which switch is connected to each of the light bulbs?

Railroad Crossing, look out for the cars. Can you spell that, without any R's ?

There are six people in a family namely M, N, O, P, Q and R.

R and O are brother and sister.

N is the brother of Q's husband.
P is the father of M and grandfather of R.

How many male members are in the family?

A shopkeeper allows people to buy a cold drink bottle in exchange for five empty bottles. A guy had a party at home and spent 77 cold drink bottles at the party. Now he has 77 empty bottles with him.

How many bottles do you think he can buy in exchange for those 77 empty bottles?

Consider all the numbers between 1 and 1 million. Among all these numbers, there is something very special about the number 8 and the number 2202. What is it?

It can be easily calculated that the digits 0 to 9 can be arranged into 3628800 distinct ten-digit numbers.

But do you know how many of these numbers are prime?

I am sure no one can have two things for dinner. what are they?