There was an aeroplane crash, every single person died, but two people survived. How is this possible?

Can you replace the question mark with the correct letter?

6 + 6 + 6 = N
7 + 7 + 7 = E
8 + 8 + 8 = R
0 + 0 + 0 = ?

John speaks the truth only once a day in a week. Below are a few hints for you:

First: Days are Sunday, Monday and so on.
Second: One day he says, "I lie on Monday and Tuesday".
Third: On the next day, he says, "Today is either Thursday, Saturday or Sunday".
Fourth: On the next day, he says, "I lie on Wednesday and Friday".

Can you identify the day on which he speaks the truth?

My friends called me Iron59 because my parents are a chemist and a mathematician. What is my real name?

I have lakes with no water, mountains with no stone and cities with no buildings. What am I?

Pronounced as one letter,
And written with three,
Two letters there are,
And two only in me.
I am double, I am single,
I am black blue and grey,
I am read from both ends,
And the same either way.

What three numbers, none of which is zero, give the same result whether they’re added or multiplied?

Which Travels Faster? Solve below famous picture riddle:

Can you find out the missing number?

? 4 5 3 5

9 5 7 10 3

Which of the following words don't belong in the group and why?
CORSET, COSTER, SECTOR, ESCORT, COURTS