The mean of Holly’s first six math quiz scores was 75%. After taking the seventh quiz, her mean score rose to 77%. What was Holly’s score on

Question

The mean of Holly’s first six math quiz scores was 75%. After taking the seventh quiz, her mean score rose to 77%. What was Holly’s score on the seventh math quiz?

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Kinsley 4 weeks 2021-10-01T04:04:43+00:00 1 Answer 0

Answers ( )

  1. Ava
    0
    2021-10-01T04:06:16+00:00

    Let x represent Holly’s score on 7th math quiz.

    We have been given that the mean of Holly’s first six math quiz scores was 75%. This means that the average on 1st 6 math quizzes is 75.

    To find the total scores on 1st 6 math quizzes, we will multiply 75 by 6 that is 75\times 6 =450.

    We will use average formula to find test scores on 7th math quiz.

    \text{Average of 7 math quizzes}=\frac{\text{Sum of scores on 7 math quizzes}}{\text{7 quizzes}}

    77=\frac{x+450}{7}

    Let us solve for x.

    77\cdot 7=\frac{x+450}{7}\cdot 7

    539=x+450

    x+450=539

    x+450-450=539-450

    x=89

    Therefore, Molly’s score on the 7th math quiz was 89.

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