Replace the question mark with the correct number, given the pair of numbers exhibits a similar relationship?

? : 3839 :: 11 : 1209

In a school, there are four subjects. Seventy percent of students study English, seventy five percent of students study Science, eighty five percent of students study Mathematics and eighty percent of students study Spanish.

Can you calculate the percentage of students that study all four subjects?

My grandson is about as many days as my son in weeks, and my grandson is as many months as I am in years. My grandson, my son and I together are 120 years. Can you tell me my age in years ?

They came out at night, without being called.
They lost at day, without being stolen.
Who are they?

Can you find a pattern and the missing number in the series given below?

100, 155, 258,? , 584, 819.

What does an Island and the letter T have in common?

Astrology starts with the alphabet A, Biology starts with B, Psychology with P and Limnology with L.

Can you find an "ology" that begins with a P?

The ages of a father and son add up to 66.
The father's age is the son's age reversed.
How old could they be?
(3 possible solutions).

f you were running a race, and you passed the person in 2nd place, what place would you be in now?

Below is the sum of symbols in each row and column in the figure. Analyzing the figure, can you find out the value of the symbols?