Why is the Hole below a Lock?

Imagine a box with two cogwheels, one big with 24 teeth and one small with 8 teeth. The big one is firmly attached to the center of the box which means it does not turn or move while the small one rotates around the big one.

How many times do you think that the smaller wheel will turn compared to the box when it turns once around the big one?

Find the next number in the series.
1 10 24 43 67 ?

What is always in front of you but can’t be seen?

What has many keys but can’t open a single lock?

Replace the question mark with the correct number in below Picture:

What does below rebus means ?

There are two candles. Both will only burn exactly for an hour. How will you use these two candles to measure forty-five minutes?

After teaching his class all about Roman numerals (X = 10, IX=9 and so on) the teacher asked his class to draw a single continuous line and turn IX into 6. The teacher's only stipulation was that the pen could not be lifted from the paper until the line was complete.

Can you make four (4) nines (9) equal 100?