What does the below image rebus riddle means ?

How will you measure 15 minutes using two hourglasses of 7 minutes and 11 minutes respectively?

Solve the rebus riddle in the picture below.

A Scientist was fifty years old in the year 2000 but he was forty years old in the year 2010. How can this be possible?

PS: It has a logical answer.

I am a type of food that is often found in the fridge and can be white in colour. What I am?
Hint 1: I am a dairy product.
Hint 2: You can spread me on the bread.

A man is shown a portrait painting. He looks closely, then tells, “Brothers and sisters have I none, but that man’s father is my father’s son!” Who is the man in the portrait?

You see me once in June, twice in November, and not at all in May. What am I?

Three people are in a room. Ronni looks at the Nile. The Nile looks at Senthil. Ronni is married but Senthil is not married. At any point, is a married person looking at an unmarried person? Yes, No or Cannot be determined.

By removing one matchstick and adding one matchstick, can you convert the word "ZOO" to an animal name?

using four eights (8) and a one (1) and one mathematical symbol , create the number 100