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

What is the centre of gravity?

Irene killed hundreds of people mercilessly and yet the police were not able to put her behind the bars. Why?

Open a Laptop which is password protected. Hint for the password is given as below:

1 mobile 3 books 2 Boards 1 night 4 balls 2 lighters 1 ghost 1 hat 3 watches

Can you count the number of lines in the below picture?

For this puzzle, you might have to find logic in something illogical. But hey, it's fun and a healthy little break from your strenuous puzzle-solving sessions.

Can you decipher the meaning in the following cluster of letters?

ITIT,NCENTCENT

When you say goodbye, I am what you need to tie.
I come as a couple and go wherever you run.
Who am I?

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

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

Jack was having a candle light dinner with his girlfriend. Suddenly a cold gush of wind entered through the open window and three of the ten candles were extinguished. Assuming that none of the other candles were extinguished.

How many candles are they left with in the end ?

Analyze and find the missing item in the sequence:
16, 06, 68, 88, __, 98