first test: 85
second test: 60
third test: x = ?
total: 70
(85 + 60 + x) / 3 >= 70
You have to divide this by the number of tests Ted will take (in this case 3).
145 + x >= 70 3
x >= 70 3 - 145
x >= 210 - 145
x >= 65
Ted has to score at least 65 on his third test.
