Total number of questions were 50.
One student got 70% of questions correct.
The percentage of questions the student got wrong was 100% - 70% = 30%
The number of questions the student got wrong were 30% of 50 which is;
[tex]\frac{30}{100}[/tex] × 50 = [tex]\frac{1500}{100}[/tex] = 15 questions.
The student got 15 questions wrong.
