If the final examination counts as two grades, what must he get on the final to earn an A in the course?

Question

To earn an A in a​ course, a boy must have a final average of at least 84%.

On the first four​ examinations, he has grades of 79​%, 85​%, 75​%, and 75​%.

If the final examination counts as two grades, what must he get on the final to earn an A in the​ course?

Answer 1

To get the average, add the numbers and divide by the number of numbers. Let "x" represent the score he gets in the final. Since the final counts for two grades, we put it in twice:

84 = (79 + 85 + 75 + 75 + x + x)/6

84(6) = 79 + 85 + 75 + 75 + 2x

504 = 314 + 2x

190 = 2x

x = 190/2 = 95

He must get a 95% on his final.