What four weights can be used to balance from 1 to 30 pounds?

Two guards were on duty outside a barracks. One faced up the road to watch for anyone approaching from the North. The other looked down the road to see if anyone approached from the South. Suddenly one of them said to the other, "Why are you smiling?"

How did he know his companion was smiling?

Christina, Allison and Lena are 3 daughters of John a well-known Mathematician, When I asked John the age of their daughters. He replied "The current age of her daughters is prime. Also, the difference between their ages is also prime."

How old are the daughters?

There is a box full of marbles,
all but two are blue,
all but two are green,
and all but two are red.

How many marbles are in the box?

Things are just as they seem, right? Well, check again.
Can you count the number of tigers in this picture ?

I look at you, you look at me, I raise my right, you raise your left. What am I?

In the image below, can you find the value of an angle(y)

Make eight squares by moving only two matchsticks.
Note- Square can be of different sizes.

On a bright sunny day, two fathers took their son fishing in the lake. Each man and son were able to catch one fish. When they returned to their camp, there were only three fishes in the basket. What happened?

PS: None of the fish were eaten, lost, or thrown back.

What time is it when an elephant sits on a fence?