Question

at a certain university, 23% of students will graduate with a math degree, 31% will graduate with a computer science degree and 7% will graduate with a degree in both math and computer science what is the probability that a student will graduate with a math or a computer science segree? A) 7% B) 47% C) 54% D) 61%

Answer 1

Answer:  B) 47%

Work Shown:

A = event that the person has math degree

B = event that the person has a computer science degree

P(A) = 0.23, since 23% of the people have a math degree

P(B) = 0.31, similar reasoning as above, just different number

P(A and B) = 0.07

P(A or B) = P(A) + P(B) - P(A and B)

P(A or B) = 0.23 + 0.31 - 0.07

P(A or B) = 0.47

The decimal value 0.47 then converts to 47% after moving the decimal 2 spots to the right.

There's a 47% chance that we pick someone who has a math degree or a computer science degree (or both).

It might help to set up a venn diagram to see why that formula above works.