Calculate the range of 20, -6, 25, 30, 21, 28, 32, 33, 34, 5, 3, 2, and 1.
Calculate the perimeter of a sector of a circle of raduis 12cm and angle 60o.
| mark | 2 | 3 | 4 |
| Frequency | 4 | 4 | y |
The table above shows the frequency distribution of marks obtained by a group of students. If the total mark is 48, find the value of y.
