There is a box full of marbles,
all but two are blue,
all but two are green,
and all but two are red.

How many marbles are in the box?

Always in you, Sometimes on you;

If I surround you, I can kill you.

What am I?

Can you replace the question mark with the correct number in the below table sequence?

Before the start of the car race, John and Jacob have the same amount of fuel in their car. With this fuel, John can drive for 4 hours while Jacob can drive five hours.
After a time they realize that the amount of fuel left in John's car is 1/4th of the fuel in Jacob's.

For how long they are racing?

I’m tall when I’m young, and I’m short when I’m old. What am I?

I am a seven-letter word but if you remove four of my letters I will have one left. What word am I?

What animal walks on four legs in the morning, two legs during the day, and three legs in the evening?

Oedipus, the king of Thebes, figured out the answer to the riddle:

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

Count the number of squares in the picture below.

What numbers should go on the bottom line?
3 6 9 15
8 2 10 12
11 8 19 27
19 10 29 39
? ? ? ?