Question

On the last 5 quizzes, Marco has earned a total of 21 out of 25 possible points. If he has a perfect score on the next several quizzes, exactly how many points will he need to bring his average up to 90%?
(a)Write a rational equation to represent this situation
(b) Solve the equation and show how how you got your answer.

Answer 1

A) The rational equation that represents the given situation in the question is; (21 + x) = 0.9(25 + x)

B) Solving the equation gives the number of points needed to bring his average to 90% as; 15 points

We are told that he earned a total of 21 out of 25 possible points.

A) Now, if he has a perfect score on the next several quizzes, it means the number of points which we will call x that he needs to bring his average up to 90% is calculated from the rational equation;

(21 + x)/(25 + x) = 90%

⇒ (21 + x)/(25 + x) = 0.9

⇒ (21 + x) = 0.9(25 + x)

B) To find the number of points, let us solve the equation in A above to get;

(21 + x) = 0.9(25 + x)

Using distributive property on the right hand side, we have;

21 + x = 0.9(25) + 0.9x

21 + x = 22.5 + 0.9x

Using subtraction property of equality;

x - 0.9x = 22.5 - 21

0.1x = 1.5

x = 1.5/0.1

x = 15 points

Read more at; brainly.com/question/12223525