what does this picture(rebus) riddle means ?

I am a white box having no key or lid.
Yet there is a golden treasure inside it.

What Am I?

what does the below rebus means?

A network of 20 x 10 squares is given to you.

Can you calculate how many unique squares and rectangles can be formed combining two or more individual squares ?

Place the numbers from 1 to 9 in the circles in a manner that each side of the triangle sums up to 17.

You and your two friends are working in a multinational company. How can you three find out the average salary of you all without disclosing your own salary to the other two?

I am the beginning of everything, the end of everywhere. I'm the beginning of eternity, the end of time and space. What am I?

On a certain day, John celebrated his birthday. Two days later, his older twin brother Jacob celebrated his birthday.

Is this even possible? How can it be?

An evil man kidnapped someone and made them take one of two pills. One was harmless, but the other was poisonous. Whichever pill the victim took, the kidnapper took the other one. The victim took their pill with water and died. The kidnapper survived. How did the kidnapper get the harmless pill?

What does this rebus riddle means ?