Math Problem Statement

Myra's test scores are shown. She has one more test for the semester. What is the minimum score that she can make on her last test and have an average greater than 90? Scores: 84, 99, 88, 82, 95, 85.

Solution

To determine the minimum score Myra needs on her last test to have an average greater than 90, let's solve this step by step.


Given Scores:

84, 99, 88, 82, 95, 85

Let xx be the score Myra gets on her last test. She has 7 tests total (6 scores given + 1 final test score).


Step 1: Express the Average

To have an average greater than 90, the total score divided by 7 must be greater than 90. Mathematically:

sum of all scores7>90\frac{\text{sum of all scores}}{7} > 90

Rearranging:

sum of all scores>90×7=630\text{sum of all scores} > 90 \times 7 = 630


Step 2: Find the Sum of the 6 Given Scores

The sum of Myra's scores is:

84+99+88+82+95+85=53384 + 99 + 88 + 82 + 95 + 85 = 533


Step 3: Solve for xx (Minimum Score Needed)

Adding the final test score xx, the total sum becomes:

533+x>630533 + x > 630

Simplifying for xx:

x>630533x > 630 - 533 x>97x > 97


Step 4: Conclusion

The minimum score Myra can make on her last test to have an average greater than 90 is:

98\boxed{98}


Verification:

If Myra scores 98: Total Score=533+98=631\text{Total Score} = 533 + 98 = 631 Average=6317=90.14>90\text{Average} = \frac{631}{7} = 90.14 > 90

Thus, a score of 98 ensures the average is greater than 90.


Would you like a more detailed explanation or verification with similar examples? Let me know!

Related Questions:

  1. How do you calculate the average of a dataset?
  2. What is the difference between "greater than" and "greater than or equal to" in inequalities?
  3. How do you determine the minimum or maximum value needed to meet a condition?
  4. Can you explain step-by-step how to solve similar word problems with averages?
  5. How would the solution change if Myra's target average was 95 instead of 90?

Tip:

To check averages quickly, always multiply the target average by the total number of items, then adjust for missing or known values.

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Math Problem Analysis

Mathematical Concepts

Averages
Inequalities
Basic Arithmetic

Formulas

Average = (Sum of all scores) / (Total number of tests)
To meet a target average: Sum of scores > Target Average * Total Tests

Theorems

Properties of Inequalities

Suitable Grade Level

Grades 6-8