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(#M40020912) SELF question Keep an EYE

. The average marks obtained by some students in an examination is 54. If 20% of the students got a mean score of 90 marks and the 30% of the students got a mean score of 20. Find the average marks of the remaining students.

vikash singh (11 years ago)

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Dr.Dipin Singh  (11 years ago)

60
If total students are x
and average of remaining students is y, then
54x= 0.2x*90 +0.3x*20+0.5x*y
54= 18+6+0.5y
0.5y=30
y=60

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Archit bhatnagar  (7 years ago)

Assume that there are total 100 students... Now according to question..
20% of students means 20 students ( i.e 20% of 100),, thus sum of marks of 20 students= 20*90=1800
similarly,
sum of marks of 30 students=30*20=600
now remaining=100-20+30=50 students
let 50 students mean be x.thus sum of marks of 50 student = 50x.
now applying the formula of average
54= (1800+600+50x)/100 ..... we divided by 100 as we have assumed the total students to be 100.
thus ans in 60

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