The absence record of students in a given term is as follows. If the mean absence for the term is 15.5 days, find the frequencies x and y.

Number of Days : 0-5 | 5-10 | 10-15 | 15-20 | 20-25
No. of Students : 15 | 16 | x | 8 | y

Number of Days : 25-30 | 30-35 | 35-40 | Total
No. of Students : 8 | 6 | 4 | 70

Question

The absence record of students in a given term is as follows. If the mean absence for the term is 15.5 days, find the frequencies x and y.

Number of Days :     0-5   | 5-10 | 10-15 | 15-20 | 20-25
No. of Students :     15    |  16  |   x   |   8   |   y

Number of Days :     25-30 | 30-35 | 35-40 |  Total
No. of Students :      8   |   6   |   4   |   70