Question

Students in an Intermediate Algebra course receive a B if the average of four tests is 80 or higher and less than 90. Suppose a student has the following scores: 80, 89, and 83. What range of scores on the fourth test would cause the students to receive а B?

Answer 1

Answer: (68, 108], which means the final test score can range from 68 to 108, but not equal 108 since 108 would give the student a 90 avg.

Explanation:

The total score of all four tests each with 100 gives the total possible total of 400. An average score of B would lie within the range of 320 and 360, with 360 being equal to an A. Thus, the final tally would have to be > or = 320 and < 360. Since the first three tests add to 252, then the fourth would have to be in the range of 320 minus 252 and less than 360 minus 252, which gives the range of 68 to less than 108 on the fourth test. Does that help?