Why is 6 afraid of 7?

If it took eight men ten hours to build a wall, how long would it take four men to build it?

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

Accidentally, two trains are running in the opposite direction and enter a tunnel that is 200 miles long. A supersonic bird that has fled the lab and taken shelter in the tunnel starts flying from one train towards the other at a speed of 1000 mph. As soon as it reaches the second train, he starts flying back to avoid collision and meets the first train again at the other end. The bird keeps flying to and fro till the trains collide with each other.

What is the total distance that the supersonic bird has traveled till the trains collided?

In this image, you can see three almost identical Doraemon images. Can you spot the odd one out from them?

You measure my life in hours
I serve you by expiring
I vanish faster when I am thin
and slower when I am thick
The wind is my energy
What am I?

Can you find out which options fits best with the missing column?

Can you spot the hidden girl in the picture below?

What has 13 hearts but no other organs?

A man stands on one side of a river, his dog on the other. The man calls his dog, who immediately crosses the river without getting wet and without using a bridge or a boat. How did the dog do it?