Question

In an examination the average marks was found to be 60.The marks of 80 candidates had to be changed from 95 to 70 each and the average came down to 55 marks.The total number of candidates attended the examination were ______?

a.800
b.300
c.400
d.650​

Answer 1

Step-by-step explanation:

80 student marks change 20 student mark remain same let 20* marks =Y

80*95+20*marks=60*number of students

80*95+Y=60n

similarly

80*70+Y=55n

subtracting

80*25=5n

n=80*5=400

option c