SSC CGL 17 Aug 2021 Shift 3 Paper

Question : 69 of 100

Marks: +1, -0

The average score of 40 students in a class test is 45 . Later on, it was found that at two places 25 was read as 35 and at one place 38 was read as 32 . What is the actual average score of the class?

$43.80$
$39.69$
$45.35$
$44.65$

Validate

Solution:

Average of 40 students is 45 marks.
Two places of 25 read 35 by mistake.
So,

35-25=10

will be subtracted
So,

10 × 2=-20

(at two places)
Similarly, 38 read as 32 so

38-32=6

Will be added.

\;\text " So, new average "\; \;\; =45-(\;{20-6}/{40})

\;\; =45-(\;{14}/{40})

\;\; =45-0.35

∴ \;\; \;\text " New average "\; \;\; =44.65

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