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

An inspection by the superintendent of St. Joseph School was scheduled on the next day. The class teacher Jenifer knew that he would be asking questions from her class and she would have to choose a pupil to answer. To offer a perfect impression over him, the teacher explained certain instructions to the students to maximise the chances of getting correct answer every time.

What did she say to the students?

Three people check into a hotel. They pay $60 for the rent of the room. After they check-in, the manager realize that the rent for the room is $55. So, he gives $5 to the bellboy and asks him to give it to them. The bellboy thinks that it will be difficult for the three people to share $5 among them and seeking the personal benefit, he pockets $2 and gives the remaining $3 to them.

Now, each person paid $20 and got back $1. In this manner, each of them paid just $19 which totals to the amount of $57. The bellboy has $2 with him and adding them, we get $59. So where is the remaining $1?

What has one letter and starts with an E?

A man was just doing his job when his suit was torn. Why did he die three minutes later?

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

What is the below Rebus indicate?

If you had a pizza with crust thickness 'a' and radius 'z', what's the volume of the pizza?

I am a seven-letter word but if you remove four of my letters I will have one left. What word am I?

Can you write down eight eights so that they add up to one thousand?