Question

Lila wants to earn an average grade of 85 across all seven tests in her Algebra course. So far, she has taken six tests, and her scores are as follows: 78, 92, 87, 80, 84, and 88.

Write an equation to represent the situation and solve it to find the grade she needs to earn on the seventh test to reach her goal of an average of 85.

(1 point)
Responses

509x7=85
509 x over 7 is equal to 85

78+92+87+80+84+88+x7 = 85
78+92+87+80+84+88+x7 = 85

78+92+87+80+84+887+x = 85
78+92+87+80+84+887+x = 85

78+92+87+80+84+886+x = 85

Answer 1

To find out what grade Lila needs on her seventh test to reach an average of 85, we first need to set up the equation.

1. Calculate the sum of the scores from the six tests:
\[
78 + 92 + 87 + 80 + 84 + 88 = 509
\]

2. Let \( x \) be the score she needs on the seventh test. The total score for all seven tests will then be:
\[
509 + x
\]

3. To find the average, we divide the total score by the number of tests (7):
\[
\frac{509 + x}{7} = 85
\]

4. Now, we will solve for \( x \):
- First, multiply both sides by 7 to eliminate the fraction:
\[
509 + x = 85 \times 7
\]
- Calculate \( 85 \times 7 \):
\[
85 \times 7 = 595
\]
- Now, we have:
\[
509 + x = 595
\]

5. Subtract 509 from both sides:
\[
x = 595 - 509
\]
\[
x = 86
\]

So, Lila needs to score **86** on her seventh test to achieve an average of 85.

The correct equation representing the situation is:
\[
\frac{509 + x}{7} = 85
\]

And the solution is \( x = 86 \).