Answers to Sections 9 and 10 of Marcel B. Finan's "A Probability Course for the Actuaries"

G. Stolyarov II
These answer keys are meant to assist students using Marcel B. Finan's A Probability Course for the Actuaries. With Dr. Finan's permission, Mr. Stolyarov wrote solutions for the problems in his study guide and is endeavoring to make the answer keys to each section publicly available. You can see his full List of Answer Keys here. Do the problems at the end of each section and then check your answers with these keys.

Dr. Finan's study guide is an excellent resource for those preparing to take Actuarial Exam 1/P on probability.

Problems that require numerical answers are answered here, but it is still the responsibility of the student to provide his or her own work for these problems. These answers are meant to enable students to independently verify the correctness of their reasoning by checking to see if the end result they obtained is correct. Questions from the study guide that require proofs or diagrams are not addressed here, as the end result of those questions is known in advance, and it is the responsibility of the student to provide the procedure for getting there.

Section 9.

Answer 9.1. 108/625=0.1728

Answer 9.2. 0.205

Answer 9.3. 7/15= about 0.46666666666667

Answer 9.4. ½=0.5

Answer 9.5a. 19/100= 0.19

Answer 9.5b. 3/5=0.6

Answer 9.5c. 31/100=0.31

Answer 9.5d. 19/60= about 0.31666667

Answer 9.5e. 19/31= about 0.6129032

Answer 9.6. 5/33= about 0.15151515151515

Answer 9.7. 2/15= about 0.133333333333

Answer 9.8. 45 of every 46 parts that make it through the inspection machine are good, but 1 of every 46 parts that make it through the inspection machine is defective.

Answer 9.9. 72/73= about 0.9863013699

Answer 9.10. 7/1912= about 0.0036610879

Answer 9.11a. 1/221= about 0.0045248869

Answer 9.11b. 1/169= about 0.0059171598

Answer 9.12. 1/114= about 0.0087719298

Answer 9.13. 80.20202020202%

Answer 9.14. 0.476

Answer 9.15a. 0.48

Answer 9.15b. 0.625

Answer 9.15c. 0.1923

Answer 9.16a. about 0.0821

Answer 9.16b. about 0.1268

Section 10.

Answer 10.1a. 0.26

Answer 10.1b. 6/13 or about 0.4615

Answer 10.2. 16/101 or about 0.1584

Answer 10.3. 1/71 or about 0.01408

Answer 10.4. 45/154 or about 0.2922

Answer 10.5. 8/19= about 0.42105

Answer 10.6. 128/583= about 0.2196

Answer 10.7. 190/289= about 0.6574

Answer 10.8. 2/5=0.4

Answer 10.9. 5/11 or about 0.4545

Answer 10.10. 0.66= 33/50

Answer 10.11a. 0.22 = 11/50

Answer 10.11b. 15/22= about 0.68181818181818

Answer 10.12a. 0.56= 14/25

Answer 10.12b. 4/7 = about 0.5714285714

Answer 10.13. 5/14= about 0.3571428571

Answer 10.14. 1/3

Answer 10.15. 15/31 = about 0.48387096777

Answer 10.16a. 17/140

Answer 10.16b. 7/17

See a list of all the answer keys to Dr. Finan's study guide for Exam 1/P here.

Published by G. Stolyarov II

G. Stolyarov II is a science fiction novelist, independent essayist, poet, amateur mathematician, composer, author, and actuary.  View profile

6 Comments

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  • Gaurav7/5/2009

    What say about answer 10.11 (b). It is mentioned that "suppose I come back with injury". This indicates he did not play soccer, so the probability should be .5*.3/(.5*.3 + .3*.1) = 5/6

  • Gaurav7/5/2009

    Hi Morrison,

    Your method is correct but you are puting wrong data. The second term in the summation should be 0.3*0.1 so the probability would be: 0.5*0.3 + 0.3*0.1 + 0.2*0.2 = 0.22.

  • Fitzwilliam7/1/2009

    I have the same answers as Charlie for 9.14. Oddly enough, my copy of the handbook seems to be missing problem 9.16. Perhaps Dr. Finan revised?

  • Morrison4/12/2009

    I think ans of 10.11(a) would be:
    0.5*0.3 + 0.2*0.1 + 0.2*0.2
    = 0.21

    Any suggestion??

  • Charlie1/30/2009

    I believe the answers to 9.14 are:
    a) ~.021
    b) from Firm A, .238; from Firm B, .286; from Firm C, .476

  • Rachel10/21/2008

    I think the answer to 9.14 is incorrect. Perhaps written in the wrong spot. First, question 9.14 has two parts, a) and b). Second, there is no way 47% of all cords are defective since the defective rates for the shipments are only 5%, 2%, and 1%.

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