Question

In order for Brady to earn a B in his biology course, his test scores must average at least 80%. On the first 5 tests, he has an average of 77%. There is one test remaining in the course. What is the minimum score Brady needs to earn on the last test to receive a B in the class? Can you give a step by step explanation?
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Answer 1

Hey there! I'm happy to help!

There were 5 tests needed to make an average of 77. These numbers have to add up to 385 (77×5) because that is what you divide by 5 to find the average which is 77.

Now, we want to find an average of 80 with 6 numbers. We multiply 80 and 6, showing us that the sum of these 6 numbers must be 480. Since 5 of these numbers are the same as with the 77 average, we know that one test score (the one Brady needs to get) is added to 385 to give us 480.

480-385=95

Therefore, Brady needs to earn a 95% on the last test to receive a B in the class.