Laila took five math tests, each worth a maximum of 100 points. Laila's score on each test was an integer between 0 and 100, inclusive. Laila received the same score on the first four tests, and she received a higher score on the last test. Her average score on the five tests was 82. How many values are possible for Laila's score on the last test?
Pick one
Solutions — 2
Solution 1
Say Laila gets a value of on her first 4 tests, and a value of on her last test. Thus,
The value has to be greater than , because otherwise she would receive the same score on her last test. Additionally, the greatest value for is (as would make as a decimal), so therefore, the greatest value can be is . As a result, only numbers work, and . Thus, the answer is .
Solution 2
1. Let be Laila's score on each of the first four tests, and let be her score on the last test. Given that her average score on the five tests was 82, we can set up the following equation:
2. Multiply both sides of the equation by 5 to clear the fraction:
3. We need to find integer solutions for and such that and , with the additional condition that .
4. Rearrange the equation to solve for :
5. Since must be greater than , we have:
6. Combine like terms:
7. Divide both sides by 5:
8. Since must be an integer, the possible values for are .
9. For each value of , we calculate using . We need to be an integer between 0 and 100, inclusive.
10. To find the range of , we substitute the minimum and maximum values of into the equation :
- When :
This value is not within the range 0 to 100.
- When :
This value is within the range 0 to 100.
11. We need to find the values of that are greater than and within the range 0 to 100. Since , we need:
12. To find the corresponding values of for in this range, we solve:
- For :
- For :
- For :
- For :
13. Therefore, the possible values for are .
The final answer is .