Can you replace the question mark with the correct number?

We have four gears with below features=> Both Gear A and D has 60 teeth=> Gear B has 40 teeth=> Gear C has 20 teeth=> Every two minutes, Gear B makes 25 full turns.What is the relative speed of Gear A and Gear B?

Can you find out what is missing?

1 3 5
2 4 ?

Hint: It's not six. Think out of the box.

Can you identify the hidden rebus in the image below?

What does this Rebus Picture means ?

Can you arrange the six given marbles in a manner that each one of them is touching all four marbles of different colours?

There is a rock group of four men that do not sing. Name It?

As you can see that fifteen matches have been used to form an arrangement. What you have to do is remove any six of them to make them ten.

A person is found murdered in his Chamber. When the crime scene is investigated, the Investigator find out that there is a calendar on which the victim has written a few numbers with his blood. The numbers are 4, 11, 11 and 4.

There are four suspects in the murder, John, Jacob, Anna and Lee. Can you find out who is the murderer?

By adding four matchsticks, can you divide the square shown in the picture into two equal parts?