Why is 6 afraid of 7?

What number should come in place of the question mark below?

Why are all black people so quick ?

Why is Saturday stronger than Monday?

A man has eighty-one cows ( numbered 1,2,3...81 as such). The beauty is that cow no. 1 gives 1ltr of milk, cow no. 2 gives 2ltrs of milk and so on. The man wants to equally distribute the cows among his nine sons so that each one of them gets the same quantity of milk.

What month of the year has 28 days?

I am the largest in my family of fifty.
The youngest of our family lives separately from the rest of the family and so do I.
I am regarded as harsh and tough.
I am so large, you cut me in two equal halves,
each half would still be larger than the second largest member of the family.
Who am I?

Do you know who was buried in John's tomb?

Can you count the number of squares in the figure below?

What is the fastest way to double your money?