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Mathematics · 2022 · 3 marks
CBSE 2022 · Region 3 · Set 3 · Q10
Find the mean of the following frequency distribution : Class Frequency $\displaystyle 0$-$\displaystyle 10$ $\displaystyle 12$ $\displaystyle 10$-$\displaystyle 20$ $\displaystyle 18$ $\displaystyle 20$-$\displaystyle 30$ $\displaystyle 27$ $\displaystyle 30$-$\displaystyle 40$ $\displaystyle 20$ $\displaystyle 40$-$\displaystyle 50$ $\displaystyle 17$ $\displaystyle 50$-$\displaystyle 60$ $\displaystyle 6$
| Class | Frequency |
| $\displaystyle 0$-$\displaystyle 10$ | $\displaystyle 12$ |
| $\displaystyle 10$-$\displaystyle 20$ | $\displaystyle 18$ |
| $\displaystyle 20$-$\displaystyle 30$ | $\displaystyle 27$ |
| $\displaystyle 30$-$\displaystyle 40$ | $\displaystyle 20$ |
| $\displaystyle 40$-$\displaystyle 50$ | $\displaystyle 17$ |
| $\displaystyle 50$-$\displaystyle 60$ | $\displaystyle 6$ |
Marking-scheme solution
| Class | \(\displaystyle x\) | \(\displaystyle f\) | \(\displaystyle d=x-25\) | fd |
| $\displaystyle 0$-$\displaystyle 10$ | $\displaystyle 5$ | $\displaystyle 12$ | -$\displaystyle 20$ | -$\displaystyle 240$ |
| $\displaystyle 10$-$\displaystyle 20$ | $\displaystyle 15$ | $\displaystyle 18$ | -$\displaystyle 10$ | -$\displaystyle 180$ |
| $\displaystyle 20$-$\displaystyle 30$ | $\displaystyle 25$ | $\displaystyle 27$ | $\displaystyle 0$ | $\displaystyle 0$ |
| $\displaystyle 30$-$\displaystyle 40$ | $\displaystyle 35$ | $\displaystyle 20$ | $\displaystyle 10$ | $\displaystyle 200$ |
| $\displaystyle 40$-$\displaystyle 50$ | $\displaystyle 45$ | $\displaystyle 17$ | $\displaystyle 20$ | $\displaystyle 340$ |
| $\displaystyle 50$-$\displaystyle 60$ | $\displaystyle 55$ | $\displaystyle 6$ | $\displaystyle 30$ | $\displaystyle 180$ |
| $\displaystyle 100$ | $\displaystyle 300$ |
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CBSE Class 10 Mathematics past-paper question from the 2022board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.