Question

monthly salaries of 30 employs in a firm 140, 139, 120, 114, 100, 88, 62, 77, 99, 103, 108, 129, 144, 148, 134, 63, 69, 148, 132, 118, 142, 116, 123, 104, 95, 80, 85, 106, 123, 133
the firm gave bonus of Rs 10, 15, 20, 25, 30, 35 for individual in the respective salary.
groups exceeding 60 but not exceeding 75, exceeding 75 but not exceeding 90, exceeding 135 but not exceeding 150.