Question

Assume that in a statistics class the probability of receiving a grade of A equals .20 and the probability of receiving a grade of B equals .30. The probability of recieving a grade of B or lower equals ---

Answer 1

80%

Explanation:

Okay, so you know that A is above B, and the probability for A is 20%.

Just do 100 - 20 and you get 80%. or .80 and you stop there since its just asking for the probability of b AND lower