Question

The probability of a student scoring 75% in class work is 0.64, and the probability of a student scoring 85% is 0.45.

Event A: The student scores 75%.
Event B: The student scores 85%.

The probability of a student scoring 85% in class work, given that they have already scored 75% in class work, is 0.55. The probability of a student scoring 75% in class work, given that they have already scored 85% in class work, is 1.
Which statement is true?

Answer 1

I'm guessing they mean 'in the top X %'

Answer 2

I mean 'above X%'

Answer 3

If you are above 85%, then it is clear (probability is 1) that you are above 75%.