Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

Prove that the below maths equation is true.

8 + 8 = 91

What is black when you buy it, red when you use it, and gray when you throw it away?

Here is a Swiss Cross. You have to make two straight cuts in the figure so that it is divided into four congruent pieces. Also, you should be able to join these pieces into a square then. Can you accept this challenge?

Your job is to measure 45 minutes if you have only two cords and matches to light the cords.

1. The two cords are twisted from various materials, so their different segments can burn at different rates.
2. Each cord burns from end to end in exactly one hour.

Describe your way of measuring the 45 minutes.

Can you find out which number multiplied by itself will give the output as 12345678987654321?

It is a nine-letter word.
The exact opposite of the phrase "friendly and outgoing"
It contains the word "over".
It starts will a vowel.

What is it?

What Adam and Eve do not have but the rest of the people have?

On my way to St. Ives I saw a man with 7 wives. Each wife had 7 sacks. Each sack had 7 cats. Each cat had 7 kittens. Kittens, cats, sacks, wives. How many were going to St. Ives?

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?