The answer is D as you can see in the picture
Just add All of the number up and divided them by 8
Not completely sure how to answer your question but all 20 questions where worth 5 points each which she would have gotten a 100 if she got all right but she got 15 which her score would be 75. I think in a ratio of correct to incorrect would be 75:100 , I'm not sure completely.
P = L + L + w + w
72 = 2(L) + 2(L-4)
Distribute
72 = 2(L) + 2(L) - 8
Add like terms
72 = 4(L) - 8
Subtract 8 from both sides
64 = 4(L)
Divide both sides by 4
16 = L
The length is 16. Now substitute that in the equation for finding w.
w = L - 4
w =