When can we add 2 to 11 and get 1 as the correct answer?

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

Who am I?

They are three errirs in this question. Can you find them?

There’s a girl who has a large family. She has an equal amount of brothers and sisters, but each brother only has half as many brothers and sisters. What’s the correct amount of brothers and sisters?

How will you measure 15 minutes using two hourglasses of 7 minutes and 11 minutes respectively?

I have 50 feet long of cloth, I need to create 50 handkerchiefs each size of 1 foot. I take one minute to cut a 1-foot handkerchief. So how long will it take to cut 50 handkerchiefs?

In a science lab, a petri dish hosts a healthy colony of yeast for an experiment. Now every minute, all the yeast cells divide into two. At noon, there was just a single cell of yeast and at 1:22, the Petri dish was half full. Can you calculate when the dish will be full of yeast?

Can you find a five letter word that is left with only two letters if one is removed?

What time is it when an elephant sits on a fence?

Take one out and scratch my head, I am now black but once was red. What am I?