The test average for Louis' calculus class is found by taking the arithmetic mean of his four best test scores. If his first four test scores are 65,82,76 and 87, what score must he get on the fifth test to raise his test average to an 85?
85 = (65+82+76+87+x)/5
Solve for x.
98
To receive a C grade, a student must average more than 77 but less than or equal to 85. If Ethan received a C in the course and had five grades of 80, 80, 74, 65, and 85 before taking the final exam, what were the possible grades for his final if there were 100 points possible? (Assume all six grades are weighted equally and let x represent the unknown score.)
To find out what score Louis must get on the fifth test to raise his test average to an 85, we need to calculate the average of his first four test scores.
To do this, we add up his four test scores: 65 + 82 + 76 + 87 = 310.
Then, we divide the sum by the number of tests, which is 4: 310 / 4 = 77.5.
Louis' current test average is 77.5.
To raise his test average to an 85, we need to find the total score he should have after taking five tests.
Multiplying the desired average (85) by the total number of tests (5), we get: 85 * 5 = 425.
To find out what score he must get on the fifth test, we subtract the sum of his first four test scores from the total desired score: 425 - 310 = 115.
Therefore, Louis must score a 115 on the fifth test to raise his test average to an 85.