Jane has a average score of 73% on three quizzes. What must she score on the next quiz to have an average of 78%?
1 answer:
Answer:
93
Step-by-step explanation:
The average is calculated as
average =
On 3 quizzes
= 73 ( multiply both sides by 3 )
sum = 219
On 4 quizzes, letting x be the score on fourth test
= 78 ( multiply both sides by 4 )
sum + x = 312 , that is
219 + x = 312 ( subtract 219 from both sides )
x = 93
She must score 93 on the next quiz
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Answer:
x = 5
Step-by-step explanation:
x + 5 = {Midpoint theorem}
2(x+ 5) = x² - x
2x + 10 = x² - x
x² - x - 2x - 10 = 0
x² - 3x - 10 = 0
x² - 5x + 2x - (5*2) = 0
x(x - 5) + 2(x - 5) = 0
(x -5)(x + 2) = 0
{x + 2 is ignored because measurement could not be in negative value}
x - 5 = 0
x = 5