Write a proportion to find how many points x a student needs to score on a test worth 50 points to get a test score of 78%.

1 answer:

4 0

The answer is: "39 points" .
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Explanation:
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" x/ 50 = 78/100 " ; in which "x" equals the number of points needed.

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To solve for "x" ;
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Look at the denominators: 50 * (what value?) = 100.

→ "100 ÷ 50 = 2" .

→ So; "50 * 2 = 100" ;

So, let us look at the numerators:

x * 2 = 78 ;

↔ 2x = 72 ;

Divide each side of the equation by "2" ; to isolate "x" on one side of the equation ; and to solve for "x" ;
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→ 78 ÷ 2 = 39 ;

The answer is: "39 points" .
_____________________________________________

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We use a z table. Look in the cells; find the values as close to 0.05 and 0.95 as we can get.

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