In an examination, the difference of the highest and the least marks is 33. When the average of marks was taken without considering the highest marks then the average was reduced by 2% but when the average of marks was taken without considering the least marks then the average of the marks was increased by 3%. If there are 76 students, find the original average of the marks of all the students?
In an examination, the difference of the highest and the least marks is 33. When the average of marks was taken without considering the highest marks then the average was reduced by 2% but when the average of marks was taken without considering the least marks then the average of the marks was increased by 3%. If there are 76 students, find the original average of the marks of all the students? Correct Answer 8.8
Let the original average of the marks of all the candidates = x
And let the highest and least marks be a and b respectively.
According to the question,
98% of x = (76x – a)/75
98% of 75x + a = 76x ----(1)
And 103% of x = (76x – b)/75
103% of 75x + b = 76x ----(2)
From equations (1) and (2)
98% of 75x + a = 103% of 75x + b
⇒ 5% of 75x = a – b
According to the question,
(a – b) = 33
∴ 5% of 75x = 33
⇒ 5 × 75x/100 = 33
By solving, x = 8.8