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Mean of 100 items is 49. It was discovered that 3 items 60, 70, 80 were wrongly read as 38,22,50 respectively. The correct mean is
$\begin {array} {1 1} (A)\;43 & \quad (B)\;78 \\ (C)\;50 & \quad (D)\;80 \end {array}$
jeemain
math
cbse
class11
statistics
easy
measures-of-dispersion-(mean)
q61
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asked
Jan 25, 2014
by
thanvigandhi_1
retagged
Sep 7, 2014
by
sharmaaparna1
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1 Answer
Sum of 100 items = $ 49 \times 100$
$ = 4900$
Sum of wrong items = $ 38 + 22+50$
$ = 110$
Sum of correct items = $ 60+70+80$
$ = 210$
$ \therefore $ correct sum = $ 4900-110+210$
$ = 5000$
$ \therefore $ correct mean = $ \large\frac{5000}{100}$
$ = 50$
answered
Jan 25, 2014
by
thanvigandhi_1
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