The average of a group of seven test scores is 80. If the lowest and highest scores are thrown out the average of the remaining scores is 78. What is the average of the lowest and highest scores?

Answer 1

If the lowest and highest are x and y, then we have, adding up all the points:

x+5*78+y = 80*7
x+y = 560-390 = 170
(x+y)/2 = 85