Correct Option: C
The average of the marks obtained in an examination by 8 students = 51
Sum of total number of 8 students in exam = 8 × 51 = 408
The average of the marks obtained in an examination by 9 other students = 51
Sum of total number of 9 students in exam = 9 × 68 = 612
| ∴ Required average = | 408 + 612 |
| 17 |
| Required average = | 1020 | = 60 |
| 17 |
Second method to find the required average , Here, n
1 = 8, a
1 = 51
n
2 = 9, a
2 = 68
| ∴ Average = | n1a1 + n2a2 |
| n1 + n2 |
| Average = | 8 × 51 + 9 × 68 |
| 8 + 9 |
| Average = | 1020 | = 60 marks. |
| 17 |
