Sarah's scores in her tests are as follows: 89, 94, 90, 90. What will be her grade in her next test if she wants to have an average of 92?
89+94+90+90 = 363
92 x 5 = 460
460 - 363 = 97
She needs a grade of 97 in her next test.
PROVE:
89+94+90+90+97 = 460
460
-----
89+94+90+90 = 363
92 x 5 = 460
460 - 363 = 97
She needs a grade of 97 in her next test.
PROVE:
89+94+90+90+97 = 460
460
----- = 92 ! YAY!
5
Correct! Well done!
:)
To find Sarah's grade in her next test, we can start by calculating the average of her previous test scores. The average is found by summing up all the scores and dividing it by the number of scores.
First, let's add up the scores: 89 + 94 + 90 + 90 = 363.
Now, we divide the sum by the number of scores to find the average: 363 / 4 = 90.75.
Sarah's current average is 90.75.
To find out what score Sarah needs on her next test to reach an average of 92, we need to set up an equation and solve for the unknown score.
Let's call the unknown score "x".
We know that the average is calculated by summing up all the scores, including the unknown score, and dividing by the total number of scores.
The equation would be: (363 + x) / 5 = 92.
To solve for x, we can multiply both sides of the equation by 5 to eliminate the denominator:
363 + x = 92 * 5,
363 + x = 460.
Now, we can isolate the x term by subtracting 363 from both sides of the equation:
x = 460 - 363,
x = 97.
Therefore, Sarah needs to score 97 on her next test to achieve an average of 92.