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In your class, you have scores of 80, 78,65, and 81 on the first four of five tests. To get a grade of C, the average of the first five tests scores must be greater than or equal to 70 and less than 80. a Solve an Inequality to find the least score you can get on the last test and still earn a C b. What score do you need if the fifth test counts as two test?​

Respuesta :

tytrellforeman

Answer:

is is 677÷87657÷88777thhsh

mhanifa

Answer:

  • a) 46
  • b) [116, 176)

Step-by-step explanation:

Average of 5 tests, if the last one equals x:

  • (x + 80 + 78 + 65 + 81)/5 =(x + 304)/5

Inequalities we get and solve:

  • (x + 304)/5 ≥ 70 ⇒ x + 304 ≥ 350 ⇒ x ≥ 46
  • (x + 304)/5 < 80 ⇒ x + 304 < 400 ⇒ x < 96
  • x = [46, 96)

a) The least score is 46

b) If fifth test counts as 2 tests, then average changes and we get inequalities below:

  • (x + 304)/6 ≥ 70 ⇒ x + 304 ≥ 420 ⇒ x ≥ 116
  • (x + 304)/6 < 80 ⇒ x + 304 < 480 ⇒ x < 176
  • x = [116, 176)

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