How many words can a pen with half refill write?

How many triangles are there on the puzzle below?

Find a 9-digit number, which you will gradually round off starting with units, then tenth, hundred etc., until you get to the last numeral, which you do not round off. The rounding alternates (up, down, up ...). After rounding off 8 times, the final number is 500000000. The original number is commensurable by 6 and 7, all the numbers from 1 to 9 are used, and after rounding four times the sum of the not rounded numerals equals 24.

Solve the equation in the image by looking at the pattern closely.

I am the one who remains awake when you sleep. But I need to rest when you awake. Who Am I?

Which Burger Is Different in below image?

People are waiting in line to board a 100-seat aeroplane. Steve is the first person in the line. He gets on the plane but suddenly can't remember what his seat number is, so he picks a seat at random. After that, each person who gets on the plane sits in their assigned seat if it's available, otherwise, they will choose an open seat at random to sit in. The flight is full and you are last in line. What is the probability that you get to sit in your assigned seat?

What is the next number in this series?

4,12,84,3612....

Which number should replace the question mark?

I can be cracked, made, told, and played. What am I?