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

p = 20 questions

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

`(3p)/(3) = (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.