Can you replace the question mark with the correct number?

Below, you will find the mathematical proof that 10 equals 9.99999?. But is that possible or there is something wrong about it? Can you find the error?

x = 9.999999...
10x = 99.999999...
10x - x = 90
9x = 90
x = 10

Here is a mathematical expression that also secretly tells a movie name. What movie is that?

What do you get if you add 2 to 100 four times?

On the occasion of Diwali, online seller companies in India are offering a big discount on Iphone14 as below.

: Flipkart offers a Flat 65% discount
: Amazon offers a 10% discount over and over again.
: Shopclues offers RS.45,000 off.

If the original cost of the iPhone is Rs.70,000 Which is the best offer for you?

How much will a 38° angle measure when looked at under a microscope that magnifies ten times?

A man embarked on a questionnaire game. He kept asking the same question to whomever he found. The answer each time was different.

Can you guess what the question was?

You may enter, but you may not come in. I have space, but no room. I have keys, but open no lock. What am I?

John and his wife were living in a rural place. On a particular day, John's wife fell ill and he called the local doctor. When the doctor picked up, he said, "Doctor, my wife is ill. She might have appendicitis."

"This can't be possible! I took out her appendix two years ago myself," the doctor explained.

When diagnosed, John's wife was found to have appendicitis. How can this be possible?

A man has a barrel filled with oil that weighs 100 pounds, and then he puts something into it. Now the barrel weighs less than 100 pounds. What did he put in the barrel?