Take away my first letter, then take away my second letter. Then take away the rest of my letters, yet I remain the same. What am I?

A mathematics teacher took exams for his students. Out of the total students, 25% passed both the tests included in the exam. However, only 42% were able to clear the first test.

Can you find out the percentage of those students who passed the first test and also passed the second test?

I always drive my customer away.

Who am I?

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

I know a ten-letter word in the English language which can be typed using only the top rows of the computer keyboard.

Before the start of the car race, John and Jacob have the same amount of fuel in their car. With this fuel, John can drive for 4 hours while Jacob can drive five hours.
After a time they realize that the amount of fuel left in John's car is 1/4th of the fuel in Jacob's.

For how long they are racing?

Can you find the company name in the pictogram below?

Can you find the largest Three-digit number whose sum is 14 and whose square is less than 5,00,000?

How many sides does a circle have?

The host of a game show, offers the guest a choice of three doors. Behind one is a expensive car, but behind the other two are goats.
After you have chosen one door, he reveals one of the other two doors behind which is a goat (he wouldn't reveal a car).

Now he gives you the chance to switch to the other unrevealed door or stay at your initial choice. You will then get what is behind that door.

You cannot hear the goats from behind the doors, or in any way know which door has the prize.

Should you stay, or switch, or doesn't it matter?