A survey of investors finds that 60% use a full service brokerage firm to invest in
Stocks, 30% trade stocks online and 24% do both. The probability that an investor
Selected at random uses a full service brokerage firm or trades stocks online is
A) 90%
B) 66%
C) 34%
D) 54%
E) 60%

Question

Quizplus · Accepted Answer

The probability that an investor uses a full service brokerage firm or trades stocks online is calculated using the formula for the union of two events: P(A or B) = P(A) + P(B) - P(A and B). Here, P(A) = 60%, P(B) = 30%, and P(A and B) = 24%. So, P(A or B) = 60% + 30% - 24% = 66%.

A Survey of Investors Finds That 60% Use a Full