In the exam the average was found to be p mark. After deducting typographical error the average marks of 120 student reduced from 90 to 70 . Due to this the average came down by 12 marks. What was the number of students who took the exam? Choices.
A) 100 B) 120 C) 200 D) 130 E) 160
Explanation :   Number of student = (90-70) * 120/12= 
<gadget id="calculator">(90-70) * 120/12</gadget>
<output>200</output>
200   Answer : 200
<result>C</result>
In the exam the average was found to be p mark. After deducting typographical error the average marks of 120 student reduced from 90 to 70 . Due to this the average came down by 12 marks. What was the number of students who took the exam?