If two's company, and three's a crowd, then whats four and five ?

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 think of a smallest +ve number such that if we shuffle the digits of the number, the new number becomes double the original number?

There is a jar in which there are two types of candies.
20 blueberries and 16 strawberries. You perform the following steps:
1) You take out two candies.
2) If the two candies are of the same flavour, you add a blueberry one otherwise, you add the strawberry one.

You repeat these two steps till there is just one candy remaining in the jar. Which flavoured candy will be left?

John went to meet his friend Jacob, but when he was about to reach the main gate, John notices that Jacob had a mighty dog who was fastened to the tree. The chain is long enough that it allows the dog to reach the main gate.

How can the John reach the main gate?

Can you find out the next digit in the following series ?

0, 0, 1, 3, 2, 6, 3, 9, 4, 12, 5, ?

If 24H in a D => 24 hours in a day.
What does "64S on CB" stand for?

Take 9 from 6, 10 from 9, 50 from 40, and leave 6.

How Come ??

I’m light as a feather, yet the strongest person can’t hold me for five minutes. What am I?

Chocolate costs 6 rupees and a Toy costs 5 rupees. If you have 32 rupees in total, how many chocolates and how many Toys can be purchased with that amount?