Answer:
80.
Step-by-step explanation:
To find the mean of an amount of numbers, you first add up all of the numbers, in this case, 90 + 80 + 70 = 240. Then, you simply divide the sum of all the numbers by the amount of numbers there are. In this case, there are three. (90, 80, and 70). So to find your answer, the equation would be:
(90 + 80 + 70) ÷ 3 = 80.
