Applied Test Series

Question

A final exam is a discrete mathematics course consisting of 20 true-false questions, each worth 3 points and 10 multiple choice questions, each worth 4 points. Suppose that the probability that a student gives a correct answer to a true-false question is 0.9 and the probability that student gives a correct answer to a multiple choice question is 0.8. What is student expected score on the final exam___

Comments

Does the answer is 86??

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we can find expected score

20*3*0.9+10*4*0.8=54+32=86

Answer 1

T/F                      MCQ

Total question :        20                        10

Points  :                       3                           4

Correct probability :  0.9                       0.8

So,  total score if all T/F are correct =20×3=60

   total score if all MCQ are correct =10×4=40

Now,  excepted score = 60×0.9 + 40×0.8=86