Question 572492: To get an A in a course, you must have an average at least 90 points for qty 4 tests. The first 3 test are worth 100 points and the 4th test is also worth 100 points (but it is worth double or counted twice). For the first three test your scores are 87, 92, and 84. What must you score on the final test to receive an A (a 90% or greater average)? Hint: This is equivalent to qty 5 test where you need to score 5 x 90 points or 450 points when adding the five scores (the last test is counted twice).
Answer by bucky(2189)   (Show Source):
You can put this solution on YOUR website! You are very close to having the correct answer.
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Do the problem like this. You already know that you need to get 450 total points on the tests.
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So far you have scored a total of 263 points. (You determine this by adding 87, 92, and 84 points.)
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Subtract the 263 points you already have from the 450 points that you need to get in total and you find out that on the last test you need to get 187 points. Divide that by 2 and you find that you need to score 93.5 on the test. Since the test counts double, a score of 93.5 will double to give you the 187 points that you need. If you cannot get half-points on the last test, you will need a score of 94 (doubling to 188 points and resulting in 451 total points) to ensure that you get a 90 overall average.
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I hope this helps you to understand the problem.
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