Can you find out the missing number in the grid?

How many pluses should we put between the digits of 987654321 to get a total of 99, and where?

The first box has two white balls. The second box has two black balls. The third box has a white and a black ball.

Boxes are labeled but all labels are wrong!

You are allowed to open one box, pick one ball at random, see its colour and put it back into the box, without seeing the colour of the other ball.

How many such operations are necessary to correctly label the boxes?

A patient was diagnosed with some ailment. He was given five different tablets to take at night at an interval of 15 minutes.

How long will it take the patient to consume all the five tablets?

What is the centre of gravity?

using four eights (8) and a one (1) and one mathematical symbol , create the number 100

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?

Can you replace the X (both small and big x) with the numbers between 1 to 19 such that all the rows of 3 numbers between X (big x) sum to 23?

On a beautiful Sunday morning, You ordered a hot tea to your hotel room and suddenly you remember an important thing that needed to be done right now will take around 3 minutes to complete.
Like most people you like your tea to be hot while drinking so, when should you pour cream in the tea?
1. straight away
2. Just people, you drink the team
3. Its does not matter

They are the five precious gems of an everyday sort and all can be found on a Tennis Court. Who are they?