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प्रश्न
If the mean of the following data is 15, find p.
| x: | 5 | 10 | 15 | 20 | 25 |
| f : | 6 | p | 6 | 10 | 5 |
उत्तर
| x | f | fx |
| 5 | 6 | 30 |
| 10 | p | 10p |
| 15 | 6 | 90 |
| 20 | 10 | 200 |
| 25 | 5 | 125 |
| N = P + 27 | `sumfx = 10p +445` |
Given mean = 15
⇒`(sumxf)/N = 15`
⇒`(10p + 445 )/ (p+ 27) = 15`
⇒ 10p +445 = 15p +405
⇒ 15p - 10p = 445 - 405
⇒ 5p = 40
⇒ `p = 40 /5`
∴ p = 8
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