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?

Find the next number in the series below

21 32 54 87 131 ?

Here is a mathematical expression that also secretly tells a movie name. What movie is that?

Find The Next Number in this series.
1, 2, 6, 42, 1806 ?

In Greek mythology, the Sphinx sat outside of Thebes and asked this riddle of all travellers who passed by. If the traveller failed to solve the riddle, then the Sphinx killed him/her. And if the traveller answered the riddle correctly, then the Sphinx would destroy herself. The riddle:

What goes on four legs in the morning, on two legs at noon, and on three legs in the evening?

Oedipus solved the riddle, and the Sphinx destroyed herself.

Below is the sum of symbols in each row and column in the figure. Analyzing the figure, can you find out the value of the symbols?

In a science lab, a petri dish hosts a healthy colony of yeast for an experiment. Now every minute, all the yeast cells divide into two. At noon, there was just a single cell of yeast and at 1:22, the Petri dish was half full. Can you calculate when the dish will be full of yeast?

A girl says this to her best friend: “I was born in 1955, and I celebrated my 17th birthday last weekend.” Her best friend thinks she’s lying, but she’s actually correct. How is that possible?

Can you place six X (crosses) in below board without making three in a row in any way ?

What 5-letter word typed in all capital letters can be read the same upside down?