Question

Suppose that the function f(p) = 3p + 30 represents the number of points you earn on a test for getting p questions correct. You earned 13 extra credit points for a project. How many questions must you answer correctly to earn an A (90 points) on the test

Answer 1

Answer:

p = 20 questions

Step-by-step explanation:

$f(p) = 3p + 30$

In order to earn 90 points on the test; equate the function to the total points to earn which is 90

3p + 30 = 90

Collect like term

$3p = 90 - 30$

$3p = 60$

Divide through by 3

$\frac{3p}{3} = \frac{60}{3}$

$p = 20 \:$

Therefore, 20 questions must be answered correctly to earn 90 points.

To check,

Since p = 20, substitute p into the function thus:

$3p + 30 = 90$

$3(20) + 30 = 90$

$60 + 30 = 90$

$90 = 90$

Note that additional 13 points earned on project is not relevant to the calculation of the points earned on the test.