If in a car race, the man who came two places in front of the last man finished one ahead of the man who came fifth, how many contestants were there?

In a mathematical quiz, you are asked the following question:

Use three 9s in a mathematical expression without dividing or multiplying to form the number one.

Can you answer the question?

I have two coins.
* One of the coins is a faulty coin having a tail on both sides of it.
* The other coin is a perfect coin (heads on side and tail on other).

I blindfold myself and pick a coin and put the coin on the table. The face of the coin towards the sky is the tail.

What is the probability that another side is also tail?

Get total of 120 by using five zeros 0,0,0,0,0 and any one mathematical operator.
Do you ?

Christina has four daughters, and each of her daughters has a brother. How many children does Christina have?

Can you think of a smallest +ve number such that if we shuffle the digits of the number, the new number becomes double the original number?

Replace each alphabet with the number (1-9) to make the below equation correct.

AB * C = DE - F = GH / I

The product of three consecutive numbers is 7980.
Then the sum of these consecutive numbers would be?

Find a 9-digit number, which you will gradually round off starting with units, then tenth, hundred etc., until you get to the last numeral, which you do not round off. The rounding alternates (up, down, up ...). After rounding off 8 times, the final number is 500000000. The original number is commensurable by 6 and 7, all the numbers from 1 to 9 are used, and after rounding four times the sum of the not-rounded numerals equals 24.

John was a very careless driver, so his owner Jacob gave him an offer that he will get an incentive of Rs.30 for every bottle box he delivered without breaking it and he will be charged Rs.90 for every bottle box he broke. Jacob gave John 100 bottles-box to deliver. After delivery, Jacob paid John Rs.2400. How many bottles-box did John break?