Alex Lose has grades of 92 90 and 84 on his first three hist

Alex Lose has grades of 92, 90, and 84 on his first three history tests. What grade must he make on his fourth test in order to keep an average of at least 90? According to my answer sheet, the answer is at least 94.

Solution

Let the grade in 4rth test be : x

So, avg of 92, 90, 84, x be 90

(92+90+84+x)/4 >= 90

(266 +x) >= 360

x >= 94 ( Solution)