This is a question related to set theory, a branch of mathematics that deals with the properties of well-defined collections of objects1. Here are some formulas that might help you solve the question2:
The complement of a set A is denoted by A’ and it contains all the elements that are not in A.
The union of two sets A and B is denoted by A ∪ B and it contains all the elements that are in either A or B or both.
The intersection of two sets A and B is denoted by A ∩ B and it contains all the elements that are in both A and B.
The difference of two sets A and B is denoted by A - B and it contains all the elements that are in A but not in B.
The cardinality of a set A is denoted by n(A) and it represents the number of elements in A.
Using these formulas, we can express the sets (P’nQ), (PnQ), and n(PnQ’) in terms of x as follows:
(P’nQ) = (P ∪ Q)’ = U - (P ∪ Q) = U - P - Q + P ∩ Q
(PnQ) = P ∩ Q
n(PnQ’) = n(P) + n(Q’) - n(P ∩ Q’) = n(P) + n(U) - n(Q) - n(P ∩ Q)
To find the greatest and smallest possible values of x, we need to use the following formula2:
n(A ∪ B) = n(A) + n(B) - n(A ∩ B)
Applying this formula to P and Q, we get:
n(P ∪ Q) = n(P) + n(Q) - n(P ∩ Q)
50 - x = 28 + 35 - n(P ∩ Q)
x + n(P ∩ Q) = 13
Since x and n(P ∩ Q) are both non-negative integers, the greatest possible value of x is 13 when n(P ∩ Q) is 0, and the smallest possible value of x is 0 when n(P ∩ Q) is 13.
I hope this helps you understand the question better.