An engineering school reports that 57% of its students were male (M), 33% of its
ID: 3072469 • Letter: A
Question
An engineering school reports that 57% of its students were male (M), 33% of its students were between the ages of 18 and 20 (A), and that 25% were both male and between the ages of 18 and 20. What is the probability of a random student being male or between the ages of 18 and 20? Your answer should be rounded to two decimal places.
Let A and B be two independent events such that P(A) = 0.39 and P(B) = 0.51. What is P(A or B)? Your answer should be given to 4 decimal places.
Let A and B be two independent events such that P(A) = 0.3 and P(B) = 0.5. What is P(A and B)? Your answer should be given to 2 decimal places.
Let A and B be two disjoint events such that P(A) = 0.48 and P(B) = 0.01. What is P(A and B)?
Explanation / Answer
Solution
Male, P(M)= 0.57
Students aged between 18 and 20, P(A )= 0.33
P(M and A) = 0.25
P(M or A) = P(M) + P(A) - P(M and A)
required probability = 0.57+0.33-0.25 = 0.65
b. P(A) = 0.39 and P(B) = 0.51
Independent event so P(A and B) = P(A)P(B)
P(A or B) = 0.39 + 0.51 - 0.39*0.51 = 0.7011