What was the original purpose of coins placed on the eyes of the deceased?

Suppose there are  [n] devices in parallel. The probability that each device works is p=[p]. What is the probability of success overall?

Consider a pair of random variables X and Y, each of which take on values on the set A={1,2,…,[n]}. The joint distribution of X and Y is a constant for all (x,y) pairs coming from the set A above. Let the random variable Z be given as the maximum of X and Y.  Find the probability that Z is less than or equal to [k].  

Which culture buried their dead with red envelopes symbolizing refuge for the soul?

Suppose you roll a pair of  4-sided fair dice. The first roll is F, the second roll is S, and the sum total is X. Find the probability  P[F=2|X=4]. 

What was the purpose of placing personal items in the tombs of ancient Egyptians?

Who held the primary responsibility for burial duties in Hebrew culture?

What was a common practice in Celtic burials for warriors?

Who ruled the Mesopotamian underworld?

Which civilization is credited with creating the concept of public burial grounds?