Question

My average grade on a set of five tests was 88%. I can remember only that the first four grades were 78%, 86%, 96%, 94%. What was my fifth grade?

A. 88
B. 86
C. 84
D. 82

Answer 1

The fifth grade was 86%.

Step-by-step explanation:

The average grade on the set of five tests was 88%. To find the fifth grade, we need to calculate the sum of all five grades and subtract the sum of the first four grades. Then, divide the result by the number of grades. Let's do the calculations:

Total sum of the first four grades: 78 + 86 + 96 + 94 = 354

Average grade on the set of five tests: 88%

To find the fifth grade: (88% * 5) - 354 = 440 - 354 = 86%

Therefore, the fifth grade was 86%. So, the answer is B. 86.

Answer 2

B. 86

Step-by-step explanation:

We know

First grade: 78%

Second grade: 86%

Third grade: 96%

Fourth grade: 94%

Average percentage: 88%

What was my fifth grade?

Let's assume the unknown grade is x; we have the equation below.

`(78+86+96+94+x)/(5)` = 88

`(354+x)/(5)` = 88

354 + x = 440

x = 86%

So, the answer is B. 86