Can you replace the question mark with the correct number?

15 caves are arranged in a circle at the temple of doom. One of these caves has the treasure of gems and wealth. Each day the treasure keepers can move the treasure to an adjacent cave or can keep it in the same cave. Every day two treasure seekers visit the place and have enough time to enter any two caves of their choice.

How do the treasure seekers ensure that they find the treasure in the minimum number of possible days?

Find the next number in the series?
2, 12, 36, 80, 150, 252, 392, _ ?

Decode below three cipher riddles:

26 L of the A
7 D of the W
1000 Y in a M

4 fathers, 2 grand-fathers and 4 sons went to watch the movie.What is the minimum number of tickets they need to buy ?

What Adam and Eve do not have but the rest of the people have?

What is the next number in this series?

4,12,84,3612....

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.

How many triangles can you count in the figure given?

Remove two matchsticks to make the below equation correct.