Question

Debbie has two stocks, X and Y. Consider the following events:

X = the event that the price of stock X has increased
Y = the event that the price of stock Y has increased

The event "the price of stock X has increased and the price of stock Y has not increased" may be written as

(A) X′ ∩ Y
(B) X or Y′
(C) X or Y
(D) X ∩ Y′

Answer 1

The correct answer is (D)

Explanation:

Given the events X and Y:

X = the price of stock X has increased

Y = the price of stock Y has increased

That means that the complement of these events are:

X' = the price of stock X has not increased

Y' = the price of stock Y has not increased

Hence, the event "the price of stock X has increased and the price of stock Y has not increased" may be written as:

X ∩ Y′