John left on a horse on Thursday , was gone for two days, and came back on Thursday after completing his work. How did that happen?

How many triangles can you count in the figure given?

You are given a cube that is made with the help of 10x10x10 smaller cubes summing up to a total of 1000 smaller cubes. You are asked to take off one layer of the cubes.
How many remain now?

What will be the best approach to finding all the prime numbers less than 75 that leave an odd reminder when we divide them with 5?

I am white when I am dirty, and black when I am clean. What am I?

I speak without a mouth, and hear without ears. I have no-body, but I come alive with the wind. What am I?

Jenifer and Jesica are having a conversation.

Jenifer: I am definitely not over 30.
Jesica: I am 28 and you are surely 5 years older to me at least.
Jenifer: No, you are at least 29.

You are told that both of them are lying throughout in the conversation. Can you find their respective ages?

Write the next letter in this sequence.
O, T, T, F, F, S, S, E, __
**Hint: It is a Number Series Puzzle

Below, you will find the mathematical proof that 10 equals 9.99999?. But is that possible or there is something wrong about it? Can you find the error?

x = 9.999999...
10x = 99.999999...
10x - x = 90
9x = 90
x = 10

What is harder to catch the faster you run?