Which number should replace the question mark?

You have to put a letter on the following to make it a meaningful word. The only challenge is that you can't use 'E'.

S E Q U E N C _

ENEMY = 2 * LINK
LINK + 2 = HELL

Then what will be TAXI + HELL? Select from the options below:
a) ROTTEN
b) DANGER
c) HEAVEN
4) MORTAL

Find the next number in the series.
1 10 24 43 67 ?

Create a number using only the digits 4,4,3,3,2,2,1 and 1. So i can only be eight digits. You have to make sure the ones are separated by one digit, the twos are separated by two digits the threes are separated with three digits and the fours are separated by four digits

The first person saw the bridge step on it and crossed,
the second person saw the bridge did not step on it but crossed,
the third person did not see the bridge did not step on it but crossed.
Who are these people?

You bought me for dinner but never eat me. What am I?

It is deaf, Dumb and Blind!!!

Still, always tells the truth. What is it?

How many times in a given day, minutes and hour clock comes in a straight line ?

How many triangles can you find in this given picture?