How many words can a pen with half refill write?

Jim and Sarah are in a long-distance relationship. Jim buys an engagement ring for Sarah and wants to mail it to her. Unfortunately, the only way to ensure the ring will be received is to place a lock on the package. Jim has locks and Sarah has locks, but neither has keys for each other’s locks. How can they make sure the ring isn’t stolen?

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

I never stop running even when I standstill. If I am formed by joining two identical bodies together, can you guess who I am?

Can you calculate the probability of getting a sum of six when a dice is thrown twice?

It is raining today at 11:59 am. What is the probability of sunny weather after 72 hours?

What is harder to catch the faster you run?

There is a circular car race track of 10km. There are two cars, Car A and Car B. And they are at the exact opposite end to each other. At Time T(0), Both cars move toward each other at a constant speed of 100 m/seconds. As we know both cars are at the same speed they will always be the exact opposite to each other.
Note, at the center, there is a bug which starts flying towards Car A at time T(0). When the bug reaches car B, it turns back and starts moving towards the car A. The speed of bug is 1m/second. After 5 hours all three stop moving.
What is the total distance covered by the bug?

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

There are a number of books on a shelf. If one book is the 4th from the left and 6th from the right, how many books are on the shelf?