[Genius if you can solve it?] Insight and intuition: a challenging IQ quiz

Because I work in dermatology

You might think, “Why dermatology when you should go to the dentist?” It says they go to a dermatology clinic, but that doesn’t mean they’re being seen as a patient—if they work there, of course they go every day.

Taro

Seeing that the eldest son is named “Ichirō” and the second son “Jirō,” you might expect the third son to be “Saburō,” but Tarō appears first—and there are four brothers. So the third son is Tarō.

5 yen

You might be tempted to say, “Subtract 100 from 110 and the answer is 10,” but if the pencil costs 10 yen, then the notebook, which is 100 yen more expensive, would be 110 yen, making the total 120 yen. It’s a problem that’s confusing precisely because the numbers are so neat.

cat's cradle

You might be inclined to think of people who build only large-scale structures, like carpenters or those in construction, right? But didn’t Tokyo Tower ring a bell? Suspension bridge, torii gate, and Tokyo Tower are all names of cat’s cradle techniques.

one time

When you imagine “99 - 1,” it looks like you could do it 99 times, but once you subtract 1 from 99 and it becomes 98, it no longer fits the premise of the question “How many times can you subtract 1 from 99?” It’s a slightly tricky quiz.

100 animals

There are 200 fish in total. Of those, 99% are guppies, which means there are 198 guppies and 2 non-guppies. If you want to make the guppies 98%, you have to reduce the number of guppies. Since there are 2 non-guppies, if you reduce the guppies from 198 by 100, you’ll have 98 guppies and 2 other fish, making it 98%. Reduce by 100 just to lower it by 1%? It might be surprising, but that’s the interesting part of this problem.

3 people

It’s tempting to reflexively think “7 − 3 = 4,” but in a game of hide-and-seek with seven people, one is the seeker. So there are six hiders to start; three are found, leaving three remaining.