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QUESTION 3For Amy to get a Cin biology, her test scores must average between 70%-80%, inclusive.She has 63%,83%, and 76% on the first three tests this semester.What range of scores on the fourth test would give her a c?between 58% and 98%, inclusivebetween 63% and 93%, inclusivebetween 70% and 80%, inclusive93% or better

Respuesta :

Given:

Test scores average between 70% - 80%

First, three test is 63%, 83%, 76%

Find-: Range score on the fourth test.

Sol:

Average scores = 70% - 80%

Let the fourth test score is "x" then

The average of all four tests is:

[tex]=\frac{63+83+76+x}{4}[/tex]

So the average range is:

[tex]\begin{gathered} \frac{63+83+76+x}{4}\ge70 \\ \\ 63+83+76+x\ge70\times4 \\ \\ 222+x\ge280 \\ \\ x\ge280-222 \\ \\ x\ge58 \end{gathered}[/tex]

For average upper range,

[tex]\begin{gathered} \frac{63+83+76+x}{4}\leq80 \\ \\ 222+x\leq320 \\ \\ x\leq320-222 \\ \\ x\leq98 \end{gathered}[/tex]

So fourth test score range is:

[tex]\text{ Between }58\%\text{ and }98\%,\text{ inclusive}[/tex]

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