I never stop running even when I standstill. If I am formed by joining two identical bodies together, can you guess who I am?

In a contest, four fruits (an apple, a banana, an orange, and a pear) have been placed in four closed boxes (one fruit per box). People may guess which fruit is in which box. 123 people participate in the contest. When the boxes are opened, it turns out that 43 people have guessed none of the fruits correctly, 39 people have guessed one fruit correctly, and 31 people have guessed two fruits correctly.
How many people have guessed three fruits correctly, and how many people have guessed four fruits correctly

It walks on 4 when its young, walks on 2 when it's older, and walks on 3 when its very old?

Who is that with a neck and no head, two arms and no hands? What is it?

Remove two matchsticks to make the below equation correct.

A certain street contains 100 buildings. They are numbered from 1 to 100. How many 9's are used in these numbers?

How much will a 38° angle measure when looked at under a microscope that magnifies ten times?

You have a 12 liters jug full of water. You have two empty 8 liters and 5 liters jug. How can you divide the water into two equal parts using these jugs?

When you say goodbye, I am what you need to tie.
I come as a couple and go wherever you run.
Who am I?

"That Restaurant always remains crowded. This is the reason why nobody goes there".

Can you find a flaw in this statement?