Math Riddles

These Math Riddles are based on math concepts and can be solved with a bit of math and logic. These fun riddles can surely give you a tough time.

Diophantus Puzzle

Diophantus was a Greek mathematician. Little is known about the life of Diophantus except for an algebraic riddle from around the early sixth century. The riddle states:

Here lies Diophantus,’ the wonder behold.
Through art algebraic, the stone tells how old:
‘God gave him his boyhood one-sixth of his life,
One twelfth more as youth while whiskers grew rife;
And then yet one-seventh ere marriage begun;
In five years there came a bouncing new son.
Alas, the dear child of master and sage
After attaining half the measure of his father’s life chill fate took him.
After consoling his fate by the science of numbers for four years, he ended his life.’

How many years did Diophantus live based on the riddle?

Riddle Answer

Catch a Train

I drive at an average speed of 30 miles per hour to the railroad station each morning and just manage to catch my train on time.

On a particular morning there was a lot of traffic and at the halfway point I found I had averaged only 15 miles per hour.

How fast must I drive for the rest of the way to catch my train?

Riddle Answer

100 Blue Eyes

On a certain island there are people with assorted eye colors. There are 100 people with blue eyes and 100 people with brown eyes. Since there are no mirrors on this island, no person knows the color of their own eyes.

The people on the island are not allowed to talk or communicate with each other in any way. They are also not aware of the number of blue or brown eyed people on the island. For all they know, they could have red eyes too. But they are allowed to observe other people and keep count of the number of people with a certain eye color. There is a rule that the people on the island have to follow – any person who is sure of their eye color has to leave the island immediately.

One day, a person comes to the island and announces to the people that he sees someone with blue eyes. Everyone knows that the person only speaks the truth. What do you think happens?

Riddle Answer