An express train takes 3 seconds to enter the tunnel which is 1 km long.
If it is travelling at 120 km an hour, how long will it take to pass completely through the tunnel?

The square root of number 121 is "11". What is the square root of the number "12345678987654321."?

Through your logical capabilities, can you make 7 an even?

Can you solve the tricky chess rebus puzzle below by ciphering the hidden meaning?

As you can see that fifteen matches have been used to form an arrangement. What you have to do is remove any six of them to make them ten.

There are two insects on a tile. Insect X is sitting on one side of the tile (point A) and Insect Y is sitting opposite on the other side of the tile (point B). Now both of them decide to change their position and thus X starts crawling to point B and Y starts crawling to point A. When they meet and pass each other in between, X takes 20 seconds to reach B and Y takes just 5 seconds to reach A.

Can you calculate the total time each of the insects took to change their positions?

Use the numbers 2, 3, 4 and 5 and the symbols + and = to make a true equation. Conditions: Each must be used exactly once and no other numbers or symbols can be used.

I can be made.
I can be cracked.
I can be told.
I can be played.

Who am I?

What is the next number in the series?

15 29 56 108 208 ?

A professor thinks of two consecutive numbers between 1 and 10.
'A' knows the 1st number and 'B' knows the second number

A: I do not know your number.
B: Nor do I know your number.
A: Now I know.

What are the four solutions for this?