The probability that a college freshman takes a math class the first semester is 0.75. The

probability that a college freshman takes an English class the first semester is 0.70. The

probability that a college freshman takes both a math class and an English class the first

semester is 0.60. Find the probability that a college freshman takes a math class or an English

class the first semester.

0.85

Explanation:

Using the addition law of probability which states that for two events A and B, the probability that A or B will occur is the sum of their individual probabilities minus the probability that both A and B will occur. The addition rule is given by the formula:

P (A or B) = P (A ∪ B) = P (A) + P (B) - P (A ∩ B)

Let probability that a college freshman takes a math class the first semester = P (A) = 0.75

probability that a college freshman takes an English class the first semester = P (B) = 0.70

probability that a college freshman takes both a math class and an English class the first semester = P (A ∩ B) = 0.60

the probability that a college freshman takes a math class or an English class the first semester = P (A ∪ B) = P (A or B)

Therefore, P (A or B) = P (A ∪ B) = P (A) + P (B) - P (A ∩ B) = 0.75 + 0.7 - 0.6 = 0.85

P (A or B) = 0.85