What is the next number in this matchsticks series riddle?

A bomb exploded in a room full of married couples and no one died. How?

Andrew’s doctor gives him three pills and tells him to take one every half hour. How much time will have passed by the time Andrew’s taken all three pills?

You are provided with a grid (as shown in the picture). Can you fill the squares with numbers 1-8 in a manner that none of the two consecutive numbers are placed next to each other in any direction (vertically, horizontally or diagonally?)

Use only one mathematical symbol and all numbers (0-9) to get a sum of 99

Be active and find the killer in the picture Riddle below.

What has six faces, but does not wear makeup, has twenty-one eyes, but cannot see?

John is a strange liar.

He lies on six days of the week, but on the seventh day, he always tells the truth.

He made the following statements on three successive days:

Day 1: "I lie on Monday and Tuesday."
Day 2: "Today, it"s Thursday, Saturday, or Sunday."
Day 3: "I lie on Wednesday and Friday."

On which day does John tell the truth?

A chess tournament is taking place on knock-out terms (the one who loses the match is out of the game).
(a) If 10 matches are played in total, how many players participated?
(b) If 20 players took part in the tournament, how many matches were played?

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