Every words stands for unique digit that makes the arithmetic equation true

SEVEN + SEVEN + SIX = TWENTY.

What are the digits ?

Using Only Five 5's and any mathematical operator make sum as 37

How many cubic feet of dirt are in a hole of one foot deep, three feet long, and two feet wide?

Nine marbles are arranged in the image below. Can you slide two marbles to form a square?

What you cannot hold but it is yours?

As easy as you can get into me, it is as hard to get out of me.

Do you know what I am?

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

Who am I?

Jigsaw captured 100 people and make them stand in a circle and all these people are labelled as Person1, Person2, Person3... Person100. He made them play a crazy game in which Person 1 shot Person 2 and pass the gun to the next person and so on until one stands alive.

Which person will survive in the end?

Considering the below equation:

V + II - VI = 10
IV - X + VIII = 20
IV - VII + VI = 30

Then, I + II + III = ?

Joseph buys three kinds of chocolates for 100 rupees. The first one is priced at 5 rupees, second one at 3 rupees and third one at 0.5 rupees.

If he bought 100 chocolates in total, how many pieces do you think he bought each chocolate?