What is both possible and impossible at the same time?

My grandson is about as many days as my son in weeks, and my grandson is as many months as I am in years. My grandson, my son and I together are 120 years. Can you tell me my age in years ?

To attend world science seminar, A famous chemist from Mexico visit
London. In the lab, the scientist was killed and his six assistants were under suspicion of killing the chemist.
Name of six assistants: Austin, Wayne, Dege, Oscaru, Lingard, and Rojo.
He left a note "76-20-44 79-16-22-7"

A local detective Jack was called to solve the case,

After reading the note, Jack instantly asked the police to arrest the murderers.

Who are the murderers?

I had an infinite supply of water and 5 litres and 3 litres jars.

How would you measure exactly 4 litres in the least number of steps?

There’s a one-story house in which everything is yellow. Yellow walls, yellow doors, yellow furniture. What colour are the stairs?

What word is represented by this rebus?

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

SEVEN + SEVEN + SIX = TWENTY.

What are the digits ?

What kind of band never plays music?

The doctor prescribed you to take one pill from the bottle every half an hour. The bottle is now left with only three pills.

How long do you think you have before you run out of pills?

What do you get if you add 2 to 100 four times?