The mean of the following distribution is 48, and the sum of all the frequency is 50. Find the missing frequencies x and y:
| Class | 20-30 | 30-40 | 40-50 | 50-60 | 60-70 |
| Frequency | 8 | 6 | x | y | ? |
a) x=5, y=9
b) x=9, y=5
c) x=6, y=8
d) x=8, y=6
