A collection of challenging quizzes for adults [Difficult]
Feeling the urge to tackle a brain-busting puzzle that seems impossible—“No one could solve this!”—might be a uniquely adult kind of curiosity.
But why do puzzles and riddles that hinge on sudden insight make your heart race? It’s because your brain is seeking that moment of activation.
This time, we’ve handpicked challenging problems for adults that test flexible thinking and ideas unconstrained by common sense.
Don’t overthink them—try looking from a slightly different angle.
The “aha!” moment is surely waiting for you.
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Difficult Logic & Exam-Type Quizzes (For Job Applicants, Examinees, and Geniuses) (1–10)
Challenging Math Quiz

Here’s a set of challenging math quizzes designed for adults to enjoy! There are 10 questions in total, including ones that test logical thinking—such as “A bat costs 4,900 yen more than a ball.
How much does the ball cost?”—as well as brain teasers like “Add one line to make the equation correct.” Every quiz will get your brain working and help loosen up a stiff mind.
Many of the problems can be solved without prior math knowledge, so even if math isn’t your strong suit, give them a try!
An elementary school problem that even University of Tokyo students struggle with

This is a quiz where you look at a drawing or photograph and write what it is in hiragana in the answer boxes.
猫の絵があれば、正しい答えは枠の中に「ねこ」と書くことです。
You might think, “Isn’t that a first-grade question?” Many of you probably feel that way.
However, it’s surprisingly difficult to figure out the answer using just the picture and the number of boxes.
Some problems clearly don’t match the number of boxes with the answer, and some pictures or photos are hard to identify at first glance.
Give it a try!
What is Lisa’s score?

This is an arithmetic problem from a junior high school entrance exam.
Look at the table and determine the score that goes in the “?”.
The key to reaching the answer is finding where the pattern lies and what kind of rule is being used.
It’s intended for elementary school students, but it’s a math problem that can make even adults think quite hard.
Apples on a deserted island

It’s a tough problem that tests your calculation skills: How many apples were there to begin with? One person eats one third of the apples, the next person eats one third of the remaining apples, then the next person eats another third, and so on.
Just writing it out like this is complicated.
If you’re confident in your arithmetic, give it a try.
Layout of the shopping center

This is a problem about determining the layout of stores inside a shopping center.
We will reason using only the text and the diagram.
Clearly separate what fits and what does not, and proceed by organizing one sentence at a time.
Solving it will feel incredibly satisfying.



