Remove two matchsticks to make the below equation correct.

What is the next number?

77, 49, 36, 18 ?

There are three identical triplets sisters. Demi is the oldest of them all and she always speaks the truth. Diana is the next one who is a liar always. Drew, the youngest of them all speaks both truth and lies randomly.

On a rainy day, a family friend Victor visited them. Since there were starkly identical, he was not able to recognize them. Thus to clarify, he asked one question to each one of them.

He started with the one standing on the left and asked, 'Which sister is in the middle of you three?' She answered, 'That's Demi.'

Then, he asked the one standing in the middle, 'What is your name?' She answered, 'I am Drew.'

Finally, he asked the one standing on the right, 'Who is standing in the middle?' She answered, 'She is Diana.'

Victor was left baffled. He asked the questions three times and received different answers every time.

Can you tell who was who?

You throw me out when you want to use me and you take me in when you don't want to use me.

Who Am I?

Intelligence Agency need to break the vault but the problem is that they are not able to break the vault.

On the vault, a text is written as:

31 11 33 33 43 45
21 25
31 24 11 31 51 41

To Break the code Intelligence Agency brings a mathematician named Joseph.
Minutes later he deciphers the code.

Whats the code?

How many minutes are there in Feb 2017?

Note: The shortest answer is the correct answer.

Can you find out what is missing?

1 3 5
2 4 ?

Hint: It's not six. Think out of the box.

A seven-year-old kid challenged his classmates that he can make the number one disappear by adding something to it.

How can he do that?

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

How do you go from 98 to 720 using just one letter?