Using it's concept, the probabilities are given as follows:
a) C. 7/20.
b) D. 15/22.
A probability is given by the number of desired outcomes divided by the number of total outcomes.
For item a, we have that there are 60 students with no curfew, and of those, 21 have no chores, hence the probability is given by:
p = 21/60 = 7/20
Which means that option C is correct.
For item b, we have that there are 66 students with no shores, and of those, 45 have a curfew, hence the probability is given by:
p = 45/66 = 15/22
Which means that option D is correct.
More can be learned about probabilities at https://brainly.com/question/14398287
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