Following are the ages (in years) of 360 patients, getting medical treatment in a hospital:

Age (in years)	10-20	20-30	30-40	40-50	50-60	60-70
Number of patients	90	50	60	80	50	30

Construct the cumulative frequency table for the above data.

The weekly wages (in rupees) of 30 workers in a factory are given below: 830, 835, 890, 810, 835, 836, 869, 845, 898, 890, 820, 860, 832, 833, 855, 845, 804, 808, 812, 840, 885, 835, 836, 878, 840, 868, 890, 806, 840, 890.

Represent the data in the form of a frequency distribution with class size 10.

The electricity bills (in rupees) of 40 houses in a locality are given below:

116, 127, 107, 100, 80, 82, 91, 101, 65, 95, 87, 81, 105, 129, 92, 75, 89, 78, 87, 81, 59, 52, 65, 101, 115, 108, 95, 65, 98, 62, 84, 76, 63, 128, 121, 61, 118, 108, 116, 130.

Construct a grouped frequency table.

Present the following as an ordinary grouped frequency table:

Given below is a cumulative frequency table:

Extract a frequency table from the above.