An arithmetic student needs at least a 70% average to receive credit for the course. If she scored 86%, 77%, and 64% on the first three exams, what is the lowest score she can get on the fourth exam to receive credit for the course?

Answer 1

There's a total of 100% for 4 exams. Her total number of points must be at least 0.7 * 400 = 280 to pass.

After three tests she has 227 points. 280 - 227 = 53.

If she gets 53% on the fourth exam, she'll pass with a 70%.

Answer 2

53