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Combined mean of two series $x_1\: and \: x_2$ when \[\] $x_1 = 210,\: x_2 = 150, \: n_1=50, \: n_2=100 $ is
$\begin {array} {1 1} (A)\;150 & \quad (B)\;160 \\ (C)\;170 & \quad (D)\;180 \end {array}$
jeemain
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class11
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measures-of-dispersion-(mean)
q77
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asked
Jan 28, 2014
by
thanvigandhi_1
retagged
Sep 8, 2014
by
sharmaaparna1
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1 Answer
Combined mean = $ \large\frac{n_1x_1+n_2x_2}{n_1+n_2}$
$ = \large\frac{50 \times 210 + 100 \times 150}{50+150}$
$ \large\frac{10500+15000}{200}$
$ = 170$
answered
Jan 28, 2014
by
thanvigandhi_1
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