Question

Markus scared 85, 92, 82, and 94 on the first four tests of the semester. His teacher has not yet told him his score on his fifth test, but did tell him that his score on the fifth test is five points lower than the average (arithmetic mean) of all five tests. Which equation could Markus use to determine the score of the fifth test, x?

Answer 1

Answer:

5(x + 5) = 353 + x

Step-by-step explanation:

i got it right on edge

Answer 2

Answer:

y — x = 5

5y — x = 353

Step-by-step explanation:

Let the fifth score be x

Let the average of all the scores be y.

But the fifth score is 5 points lower than the average ie

y — x = 5 (1)

The average of the scores is the sum of all the scores divided the number of scores. This is written as

y = (85 + 92 + 82 + 94 + x) /5

y = (353 + x) /5

Multiply through by 5

5y = 353 + x

Rearrange the equation

5y — x = 353 (2)

The equation Markus will use to determine the x is given as

y — x = 5

5y — x = 353