Quickly Solve this riddle

7 - 4 + 3 * 0 + 1 = ?

There are forty elephants and they have forty-fore heads. How can this be possible?

Assume there are approximately 5,000,000,000 (5 billion) people on Earth. What would you estimate to be the result, if you multiply together the number of fingers on every person's left hand? (For the purposes of this exercise, thumbs count as fingers, for five fingers per hand.) If you cannot estimate the number then try to guess how long the number would be.

The doctor advised his patient to take a tablet after every fifteen minutes. He gave him five tablets in total.

How much time will he take to have all the five tablets?

When I got four, I have it none.
When I got two, I have it some.
When I got none, I have it all.

What is it?

The Puzzle: A girl, a boy, and a dog start walking down a road.

They start at the same time, from the same point, in the same direction.

The boy walks at 5 km/h, the girl at 6 km/h.

The dog runs from boy to girl and back again with a constant speed of 10 km/h. The dog does not slow down on the turn.
How far does the dog travel in 1 hour?

Can you find the dog hidden in a group of pandas?

Find out the missing number in the picture attached:

Can you identify the famous TV character from the rebus below?

A man dies of old age on his 25 birthday. How is this possible?