Question 839330: Jennifer's 5 test scores in her science class are 87, 72, 94, 82, and 85. What is the minimum that she can score on her last 100-point exam so that her average is at least a 90?
Answer by josh_jordan(263)   (Show Source):
You can put this solution on YOUR website! To solve this word problem, we need to convert it into an equation. To do this, let's look at what we know:
1. We know that, to find the average of a set of numbers, we add the numbers together and divide that result by the number of numbers we have.
2. We know that, if Jennifer takes 6 tests, she must average at least 90.
Now, we can create an equation:
We need to then solve for x by isolating x to the left side of our equation. To do this, we need to first get rid of the division on the left. We do this by multiplying both sides of the equation by 6. This gives us:
Combine all like terms on the left side by adding them together. This gives us:
Subtract 420 from both sides of the equation, which gives us:
This means that Jennifer must score 120 on her last test to receive at least a 90% average. HOWEVER, if there are only 100 points possible on the final exam, she cannot receive a final average of 90% or higher. The highest possible score she can receive on the last exam is 100, and this would give her an average of approximately 87%
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