The average marks of 18 students in an examination were 60. It was later
found that the marks of one student had been wrongly entered as 63 instead
of 36. The correct average is:
A) 59 B) 59.5 C) 58 D) 58.5
Answers
Answered by
4
Answer:
D) 58.5
Step-by-step explanation:
Average=Total marks/No. of students
==>60=Total Marks/18
==>Total Marks= 18×60
==>Total Marks=1080
When marks amended then,
=>Total Marks=1080-27
=>Total marks=1053
=>Now,
Average=Total/frequency
Average marks =1053/18
=>Average Marks=58.5
Answered by
2
Answer
Simple Trick To Slove Such Types Of Questions :
⇒ Difference in the mark = 36 - 63 = -27
⇒ Reduction in average per student = Difference/number of students = -27/18 = -1.5
∴ New average = 60 - 1.5 = 58.5
Perfect Solution :-
⇒ Wrongly caculated total of class = average × number of students = 60 × 18 = 1080
⇒ Original total = 1080 - 63 + 36 = 1053
∴ New average = 1053/18 = 58.5
HoPe iT HeLpS YoU
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