# Math Riddles

### Math Riddle – 1

A 26″ x 26″ square metal plate needs to be fixed by a carpenter on to a wooden board. The carpenter uses nails all along the edges of the square such that there are 27 nails on each side of the square. Each nail is at the same distance from the neighboring nails. How many nails does the carpenter use?

What if the metal plate is in the shape of a regular polygon (e.g., pentagon, hexagon, heptagon, octagon, etc.)? Try generalizing the above result to the case of a regular polygon.

### Math Riddle – 2

A painting job can be completed by 5 painters in 37 days. If 10 more painters join the team 7 days after starting work on the job, then how many more days are required to complete the job?

The number of days for the job is inversely proportional to the number of painters. So, is ‘number of days × number of painters = constant’?

What assumptions were made to arrive at the solution?
Is something assumed about the output of the painters?

#### Vineet Patawari

Hi, I'm Vineet Patawari. I fell in love with numbers after being scared of them for quite some time. Now, I'm here to make you feel comfortable with numbers and help you get rid of Math Phobia!

## 11 thoughts to “Math Riddles”

1. anupma says:

1st riddle=27×2 +25×2=104

2. Govind K. Bahroos says:

10 days only

1. Nice riddle and thanks for the same.This kind of problems although simple will make people think for some time atleast.For the first problem 27+26+26+26 nails.

3. Govind K. Bahroos says:

10 Days only.

4. math1

26*number side of regular polygan

math2

10 days( if all painter gives equal output)

5. Mohit says:

Okay.. the website server has some problem.. 🙂 even my post is at 17:30..

6. Mohit says:

Moderator, interestingly all the above posts were exactly at 17:30 hours.

Puzzle lovers, what is the probability of that happening? Or is it programmed to do so?