SOLUTION: You earned the following scores on five science tests: 75,82,90,84, and 71. You want to have an average score of at least 80 after you take the sixth test. a. Write and solve an i

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Question 119438This question is from textbook Algebra 1
: You earned the following scores on five science tests: 75,82,90,84, and 71. You want to have an average score of at least 80 after you take the sixth test.
a. Write and solve an inequality to find the possible scores that you can earn on your sixth test in order to meet your goal.
b. the greatest score you can earn on a test is 100. Is it possible for you to have an average score of 90 after the sixth test? Explain you reasoning.
This question is from textbook Algebra 1

Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
You earned the following scores on five science tests: 75,82,90,84, and 71. You want to have an average score of at least 80 after you take the sixth test.
:
a. Write and solve an inequality to find the possible scores that you can earn on your sixth test in order to meet your goal.
:
Let x = the required score to have an average of at least 80
%2875+%2B+82+%2B+90+%2B+84+%2B+71+%2B+x%29%2F6 => 80
:
Multiply equation by 6 to get rid of the denominator, add up the scores
402 + x = 6(80)
x => 480 - 402
x => 78 required for at least an 80
:
b. the greatest score you can earn on a test is 100. Is it possible for you to have an average score of 90 after the sixth test? Explain you reasoning.
:
Not possible, none of the 5 scores are above 90
:
To confirm this, you can use the above equation: substitute 100 for x and see what the average is
%28402+%2B+100%29%2F6 = 83.67