If the mean height of 3 boys is 142 cm. and the mean height of another 7 students is 145 cm., then the mean height of 10 students.
If the mean height of 3 boys is 142 cm. and the mean height of another 7 students is 145 cm., then the mean height of 10 students.
A) 144 cm
B) 144.1 cm
C) 144.2 cm
D) 144.4 cm
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Correct option is (B) 144.1 cm
The mean height of 10 boys \(=\frac{3\times142+7\times145}{10}\)
\(=\frac{426+1015}{10}\)
\(=\frac{1441}{10}\) = 144.1 cm
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