On the last math quiz, there were four A's, two B's, five C's, and one D's. If the math quizzes were returned to the students in random order, what is the probability that the first quiz returned to a student was an A or a B?
There are 12 grades total. To find the probability of A OR B, you would add the amount of A and B grades together. amt. of A's- 4 amt. of B's- 2.
2+4=6
probability of an A or B is 6/12 or 1/2
To find the probability of the first quiz being an A or a B, we need to calculate the total number of favorable outcomes (A or B) and divide it by the total number of possible outcomes.
First, let's find the total number of quizzes. The given information tells us that there were four A's, two B's, five C's, and one D's, so the total number of quizzes is:
Total quizzes = A + B + C + D = 4 + 2 + 5 + 1 = 12
Next, let's find the total number of favorable outcomes, which in this case are the number of A's and B's. So:
Total favorable outcomes = A + B = 4 + 2 = 6
Finally, we can calculate the probability by dividing the favorable outcomes by the total possible outcomes:
Probability = Total favorable outcomes / Total quizzes = 6 / 12 = 1/2
Therefore, the probability that the first quiz returned to a student was an A or a B is 1/2 or 50%.