Question 1110066
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The problem is over-constrained; however, the constraints are consistent with one another.<br>
To calculate the probability that he passes both classes, you only need to multiply the probabilities of his passing each class: 0.5*0.6 = 0.3.<br>
With those numbers, the given information that there is an 80% chance of passing at least one of the courses is extraneous.<br>
P(pass both) = 0.3
P(pass accounting only) = 0.5-0.3 = 0.2
P(pass english only) = 0.6-0.3 = 0.3<br>
It follows (without having to be specified in the problem) that
P(pass at least one) = 0.3+0.2+0.3 = 0.8.<br>
So the more complicated calculation shown by the other tutor, while valid, is more work than is required.