What will you call your mother's brother's brother-in-law?

A father's child, a mother's child, yet no one's son.

Who am I?

Teacher ask the student

'Why are you standing on that chair in music class ?'.

what did student replied ?

Can you decipher these quotes by Albert Einstein?
Blf xzm mvevi hloev z kilyovn lm gsv ovevo lm dsrxs rg dzh xivzgvw.

Can you find out the remainder when 3^300 is divided by 5?

Which is the smallest number that you can write using all the vowels exactly once?

I am five letter word that is under you.
If you remove my 1st letter, then I am over you.
If you remove my 1st and 2nd letters then I am all around you.

Who am I?

Four people need to cross a rickety bridge at night. Unfortunately, they have only one torch and the bridge is too dangerous to cross without one. The bridge is only strong enough to support two people at a time. Not all people take the same time to cross the bridge. Times for each person: 1 min, 2 mins, 7 mins and 10 mins. What is the shortest time needed for all four of them to cross the bridge?

Cristina leaves home and then she makes exactly 3 left turns and returns home where she found 2 girls wearing the mask.

Who are these two masked girls?

Solve the following series:
AZ, GT, MN, __, YB