Can you solve this tricky maths equation problem by replacing it? mark with the correct symbol?

19834 -----: 187
15921 -----: 153
17561 -----: 139
13734 -----: ???

John was piloting a plane behind a car but was never able to overtake it. Why?

I have no doors but I have keys, I have no rooms but I have space, you can enter but you can’t leave! What am I?

They are the five precious gems of an everyday sort and all can be found on a Tennis Court. Who are they?

A patient was diagnosed with some ailment. He was given five different tablets to take at night at an interval of 15 minutes.

How long will it take the patient to consume all the five tablets?

Here is what you have to do. You have to throw a ball as hard as you can but it must return back to you even if it does not bounce at anything. Also, you have nothing attached to the ball. There is no one on the other end to catch that ball and throw it back at you.

How will you do it?

A dead body is found outside a multi-story multinational company. The case is reported and a homicide detective is called on the crime scene.

He looks at the body and then towards the building. From the position of the body, it is evident that the victim committed suicide. He goes to the first floor of the building and then walks in the direction of the dead body, opens the window and toss a coin in the air.

He goes to second floor and again repeats the process. He keeps doing this till he is done on all the floors. Then he returns back to the floor and tells his team that it is a murder.

How in heaven did he deduce that?

What comes
Once in a Year
Twice in a Month
4 times in a Week
6 times in a Day

If you toss a coin 10 times and it lands heads up every time, what are the chances it will land heads up if you toss it again?

A sundial has the fewest moving parts of any timepiece. Which has the most?