Use only one mathematical symbol and all numbers (0-9) to get a sum of 99

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?

John replied, when asked how old he was. In 2 years he will be twice as old as he was five years ago.' How old is he ?

I have thought of a number that is made up by using all the ten digits just once. Here are a few clues for you to guess my number:

First digits is divisible by 1.
First two digits are divisible by 2.
First three digits are divisible by 3.
First four digits are divisible by 4.
First five digits are divisible by 5.
First six digits are divisible by 6.
First seven digits are divisible by 7.
First eight digits are divisible by 8.
First nine digits are divisible by 9.
The number is divisible by 10.

Can you find out the number ?

What is the end of everything?

The centre of the third figure is empty. What digit should fit inside?

Two prisoners Jack and Jill are locked in a cell.
There is open window approx 40 feet above the ground of the cell.
They are never able to reach there.

Then they plan to escape by a tunnel and they start digging out.
After digging for more than 20 days, Jill comes with the different plan and they escaped.

what was the plan ?

What has many teeth, but cannot bite?

You have to put a letter on the following to make it a meaningful word. The only challenge is that you can't use 'E'.

S E Q U E N C _

I have cities, but no houses. I have mountains, but no trees. I have water, but no fish. What am I?