13/15 is about 87%, which is typically a "B". This may vary depending on the grading rules at your school
87% or B+
66.67% D
93.
83%
77%
A (96%)
75% or C
83% or B
your grade would be 80% or a B-
If you miss 5 questions on a 20-question test, you answered 15 questions correctly. To find your grade, divide the number of correct answers (15) by the total number of questions (20) and then multiply by 100 to get a percentage. This results in a grade of 75%.
75% or a "C".
15 / 31 * 100% = 48.39% Usually you need to obtain 50% or over to pass an exam or test.