Maths Set Theory Puzzle

In a school, there are four subjects. Seventy percent of students study English, seventy five percent of students study Science, eighty five percent of students study Mathematics and eighty percent of students study Spanish.

Can you calculate the percentage of students that study all four subjects?




Similar Riddles

John is found dead in a bare field. Nobody killed John,
John did not commit suicide.

Inspector Jacob found a bag just a few meters away from John which could save his life. What was in the bag?

Asked by Neha on 04 Dec 2025


When you say goodbye, I am what you need to tie.
I come as a couple and go wherever you run.
Who am I?

Asked by Neha on 12 Oct 2025

The picture shows the dice results in each couple of throws. If they are actually following a pattern, can you find out the missing one?

Next Dice Movement

Asked by Neha on 02 Dec 2023


A man and his wife were doing missionary work near the city of Nairobi in the country of Kenya in eastern Africa. Their housing had not yet been completed, so the man, the woman, and their six year old daughter were spending a few nights in the jungle in three small pup tents. During their third night there, the woman was awakened by the call of a hyena passing by, so she got out of her tent to see if her young daughter had been frightened by the noise. As she peered into her daughter's tent she was surprised to see the dark figures of lion, a panther, and a cheetah which were curled up next to her daughter. Seeing her daughter was asleep and unharmed, the woman slowly and quietly withdrew from the tent, and simply returned to her own tent and went back to bed. How could this child's mother leave her daughter in such a dangerous situation, and simply ignore what she had just witnessed without intervening in some way? How can such emotional coldness ever be explained; or is there something here we are missing?

Asked by Neha on 04 Apr 2022

You have a roll of cloth 1km long. You have a machine which cuts this roll into pieces of 10-meter-long cloth.

How long would it take for the machine to cut the roll if each cut took 4 secs?

Asked by Neha on 15 Aug 2024

Take number 1000 and then add 20 to it.
Now add 1000 one more time.
Now add 30.
Now add 1000 one more time.
Now add 40.
Now add 1000 one more time.
Now add 10.

What is the total?

Asked by Neha on 18 Jan 2024


What has one eye, but can’t see?

Asked by Neha on 16 Jul 2025

It has horns but can’t beep. It is like to bleat but It is not a sheep. What is it?

Asked by Neha on 30 Oct 2025

A worker is to perform work for you for seven straight days. In return for his work, you will pay him 1/7th of a bar of gold per day. The worker requires a daily payment of 1/7th of the bar of gold. What and where are the fewest number of cuts to the bar of gold that will allow you to pay him 1/7th each day?

Asked by Neha on 05 Mar 2024


Today is a very icy and cold morning in Newcastle. Mr Shearer, an office bus driver arrived to pick up the employees from the last stop. Shearer suddenly remembers that he needs to pick a newly joined 4miles to the north. Mr Shearer lost his direction compass, a few minutes later Shearer is able to figure that he is moving in the correct direction i.e. north. How did Shearer know that he is moving in the correct direction?

Asked by Neha on 01 Aug 2024

Hot Articles

Amazing Facts

Jigsaw puzzles

Jigsaw puzzles soared in popularity during the great depression, as they provided a cheap, long-lasting, recyclable form of entertainment.