proportion and persentage

Question

in a science class test,jamie solved 42 correct answers and 18 incorrect answer.what is the percentage of correct answers?

Answer 1

The main formula for percentage calculations is:

I = P x R

P = Principal. The original number/value.

R = Rate. The percentage.

I = Interest. The part of the principal that is represented by the percentage.

So, if you want to get to the percentage (R) you use:

R = I/P

The principal in this case is the total of questions: 42 + 18 = 60

The interest is the 42 correct answers.

R = 42 / 60 = 0.7 = 70%