Question

Ruth has taken four quizzes in her French class. Her scores

on these quizzes are 84, 86, 90, and 88. The score of her
test will be counted twice in her mean. If she takes only
these four quizzes and one test, what is the lowest score
she can earn on her test and have a mean score of at least
90?

Answer 1

The lowest score she can earn on her test is 96

Explanation:

To find mean, first find the sum of the values by adding them all up and then divide the sum by the number of values in the data set

Given - Scores from 4 quizzes = 84, 86, 90 and 88

Test scores will be counted twice in the mean

Mean score should be atleast 90

If mean score is to be 90 the sum of the scores should be = 90 * 6 = 540 (4 quizzes and 2 test score as its counted twice)

Sum of the score from 4 quizzes = 84 + 86 + 90 + 88 = 348

Total score required from test = 540 - 348 = 192 / 2 = 96

So Ruth needs to score atleast 96 in her test to have a mean score of 90