Brenda’s scores on the first three of four 100-point science tests were 95, 92, and 89. What score does she need on her fourth science test to ensure an average score of at least 93?

A) X ≥ 96
B) X ≤ 90
C) X ≥ 88
D) X ≤ 92

Question

Brenda’s scores on the first three of four 100-point science tests were 95, 92, and 89. What score does she need on her fourth science test to ensure an average score of at least 93?

A) X ≥ 96
B) X ≤ 90
C) X ≥ 88
D) X ≤ 92

anonymous · Answer

Please Help

mathstudent55 · Answer

Let's say the score on the 4th test is x.
How do you find the average of the scores of all 4 tests?

anonymous · Answer

i'm not sure

mathstudent55 · Answer

To find the average of 4 scores, you add all scores together and divide the sum by 4.

mathstudent55 · Answer

The average fo the 4 scores is:

$\dfrac{95 + 92 + 89 + x}{4} $

Ok?

anonymous · Answer

aww thank you so much

mathstudent55 · Answer

To have an average of at least 93, it means that the average must be greater than or equal to 93.

mathstudent55 · Answer

You must solve this inequality for x:

$\dfrac{95 + 92 + 89 + x}{4} \ge 93$

mathstudent55 · Answer

$\dfrac{276 + x}{4} \ge 93$

$276 + x \ge 93 \times 4$

$276 + x \ge 372$

$x \ge 96$

mathstudent55 · Answer

wlcm

anonymous · Answer

so its A