Look at the below sequence of letters and tell us what the next letter should be:

O T T F F S S ?

Can you find the missing letter in the sequence?
S - T - I - L - ? - T - F - Y - C

Count the number of balls in picture below:

Three cars are driving on a track that forms a perfect circle and is wide enough that multiple cars can pass anytime. The car that is leading in the race right now is driving at 55 MPH and the car that is trailing at the last is going at 45 MPH. The car that is in the middle is somewhere between these two speeds.
Right now, you can assume that there is a distance of x miles between the leading car and the middle car and x miles between the middle car and the last car and also, x is not equal to 0 or 1.
The cars maintain their speed till the leading car catches up with the last car and then every car stops. In this scenario, do you think of any point when the distance between any two pairs will again be x miles i.e. the pairs will be x distance apart at the same time ?

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

You have a three-gallon and a five-gallon measuring device. You wish to measure out four gallons.

What number does the below three word/phrase identify and why?
1. Deck
2. Year
3. Singing in the Rain

Can you name four days which start with the letter 'T'?

On the dull night when the blonde was dozing, she heard an odd clamour and she saw that there was a bizarre man with a gun simply outside her home. So she raced to the telephone to call the police, however, she can't dial 911. Why?

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?