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?

100 prisoners are stuck in the prison in solitary cells. The warden of the prison got bored one day and offered them a challenge. He will put one prisoner per day, selected at random (a prisoner can be selected more than once), into a special room with a light bulb and a switch which controls the bulb. No other prisoners can see or control the light bulb. The prisoner in the special room can either turn on the bulb, turn off the bulb or do nothing. On any day, the prisoners can stop this process and say "Every prisoner has been in the special room at least once". If that happens to be true, all the prisoners will be set free. If it is false, then all the prisoners will be executed. The prisoners are given some time to discuss and figure out a solution. How do they ensure they all go free?

What has one letter and starts with an E?

Can you fill the blank with the correct number?

6 30 870 756030 _____

There is one thing that goes round the house and also inside the house but never even share a brief touch. What is it?

I never stop running even when I standstill. If I am formed by joining two identical bodies together, can you guess who I am?

You want to boil a two-minute egg. If you only have a three-minute timer (hourglass), a four-minute timer and a five-minute timer, how can you boil the egg for only two minutes?

Here is a conversation between a couple who both are software professionals.

Husband: Hey! What is your date of birth?
Wife Replied Angrily: It is 591062400
Husband after doing some calculations replied, "Got It".

What is the DOB of the wife?

What do you think with the below Picture ?

Forwards I am heavy, backward I am not. What am I?