the average marks obtained by 120 students in an examination is 30. if the average marks of passed students is 40 and that of the failed students is 10, what is the 25% of the number of students who passed the examination ?
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Answer:
Total marks scored = 120x30 = 3600
Let number of students passing be x. Their average is 40.
Number of students failing is 120-x. Their average is 10.
Now, x(40) + (120-x)(10) = 3600
Solving:
40x + 1200 -10x = 3600
30x +1200 = 3600
30x = 2400
x = 2400/30 = 80
So number of students passing = 80
25% of students passing = 25/100 x 80 = 20
ANSWER IS 20
Answered by
0
Answer:
E)NON OF THESE
Step-by-step explanation:
see 25%=25/100
therefore 40 multiply by 25/100
=4multiply by 5/2
=2mltiply by 5
=10
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