The mean of the following frequency distribution is 62.8 . Determine the values of f_1 and f_2 . Class: 0-20 20-40…

CBSE Class 10 Maths PYQ · Statistics · Find Freuency · 5 Marks · July 2025 · Standard

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795 Marks · July 2025 · Standard

The mean of the following frequency distribution is $62.8$. Determine the values of $f_1$ and $f_2$.
Class: $0-20$ $20-40$ $40-60$ $60-80$ $80-100$ $100-120$ Total
Frequency: $5$ $f_1$ $10$ $f_2$ $7$ $8$ $50$

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Correct table
Mean = $62.8$
$\frac{2060 + 30f_1 + 70f_2}{50} = 62.8$
$\Rightarrow 30f_1+70f_2 = 1080$ or $3f_1 + 7f_2 = 108$ --- (1)
Also, $30 + f_1 + f_2 = 50$
$\Rightarrow f_1 + f_2 = 20$ --- (2)
Solving (1) and (2), we get
$f_1 = 8$ and $f_2 = 12$