Question

Going into the final​ exam, which will count as two​ tests, Brooke has test scores of 79 comma 82 comma 70 comma 63 comma and 94. What score does Brooke need on the final in order to have an average score of​ 80?

Answer 1

Brooke needs 172 on the final exam.

Explanation:

Brooke has test scores of 79 comma 82 comma 70 comma 63 comma and 94.

Total test = 5

Total score = 79+82+70+63+94 = 388

It is given that final​ exam will count as two​ tests.

Let Brooke needs x on the final exam.

Total number of tests after final exam = 7

Formula for Average:

`Average=\frac{\text{Sum of observations}}{\text{Number of observation}}`

`Average=(388+x)/(7)`

Average scare is 80.

`80=(388+x)/(7)`

Multiply both sides by 7.

`560=388+x`

Subtract 388 from both sides.

`560-388=x`

`172=x`

Therefore, Brooke needs 172 on the final exam.

Answer 2

92

Explanation:

Using the formula to calculate the average, and considering we know the result of the first 5 tests, we can calculate the score needed for the final exam in order to get an 80, using the following formula:

Average = (Sum of all the tests) / (number of tests)

where:

average = 80

x = score she needs to get for the final exam

number of tests = 6

Therefore,

80 =
`(79+82+70+63+94 +x)/(6)`

Finding a common denominator we have to multiply 80 by 6:

79 + 82 + 70 + 63 + 94 + x = 6*80

Adding the terms and multiplying:

388 + x = 480

So, x = 480 - 388

x = 92

Therefore, Brooke needs to get a 92 on her final exam in order to get an average score of 80.