Question

Experience with the Finite Mathematics course at a certain college suggests that of those students who get a grade of C or better on exam​ I, 90% get a C or better on exam II. Of those who get D or F on exam​ I, 70% get a D or F on exam II. This year​ 80% got C or better on exam I. Find the proportion of Finite Mathematics students who are likely to get D or F on exam II.

Answer 1

The proportion of Finite Mathematics students who are likely to get D or F on exam II is 0.22 = 22%.

Explanation:

We have these following proportions:

80% got C or better on exam I. Of those, 90% are likely to get a C or better on exam II. So 100-90 = 10% are likely to get D or F.

20% got D or F on exam II. Of those, 70% get a D or F on exam II.

Find the proportion of Finite Mathematics students who are likely to get D or F on exam II.

10% of 80% plus 70% of 20%. So

0.1*0.8 + 0.7*0.2 = 0.22

The proportion of Finite Mathematics students who are likely to get D or F on exam II is 0.22 = 22%.