In the exam the average was found to be p mark. After deducting typographical error the average marks of 90 student reduced from 75 to 60 . Due to this the average came down by 15 marks. What was the number of students who took the exam?	Choose the correct option:
A) 90  B) 100  C) 110  D) 130  E) 160
Explanation :   Number of student = (75-60) * 90/15= 
<gadget id="calculator">(75-60) * 90/15</gadget>
<output>90</output>
90   90nswer : 90
<result>A</result>
In the exam the average was found to be p mark. After deducting typographical error the average marks of 90 student reduced from 75 to 60 . Due to this the average came down by 15 marks. What was the number of students who took the exam?