Piyush, Harmesh and Atul are partners. Each partner regularly withdrew Rs. 20,000 per month as given below
a) Piyush withdrew in the beginning of the month;
b) Harmesh withdrew in the middle of the month and
c) Atul withdrew at the end of the month.
Interest on drawings charged for the year ended 31st march was Rs. 15,600, Rs. 14,400 and Rs. 13,200 respectively. Determine the rate of interest charged on drawings.