A student missed 12 problems on a history test and received a grade of 70%. If all the problems were of equal value, how many problems were on the test?

Question

A student missed 12 problems on a history test and received a grade of 70%. If all the problems were of equal value, how many problems were on the test?

Answer 1

He missed 30% of the questions because the grade is 70%

 

12/N = 30% = 0.3 where N is the number of problems

 

12 = 0.3 * N

 

N = 12/ 0.3 = 120/3 = 40

 

40 questions.

12 incorrect.

28 correct

 

12/40 = 3/10 = 30%

28/40 = 7/10 = 70%