Mathematics
If the mean of the following distribution is 24, find the value of a.
| Marks | No. of students |
|---|---|
| 0 – 10 | 7 |
| 10 – 20 | a |
| 20 – 30 | 8 |
| 30 – 40 | 10 |
| 40 – 50 | 5 |
Measures of Central Tendency
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Answer
| Marks | No. of students (f) | Class mark (y) | fy |
|---|---|---|---|
| 0 – 10 | 7 | 5 | 35 |
| 10 – 20 | a | 15 | 15a |
| 20 – 30 | 8 | 25 | 200 |
| 30 – 40 | 10 | 35 | 350 |
| 40 – 50 | 5 | 45 | 225 |
| Total | ∑ f = 30 + a | ∑ fy = 810 + 15a |
By formula,
Hence, the value of a = 10.
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