Average Due Date - Doubt ??

X wants to save interest of ` 150. The yearly interest is ` 20,000*18%  = ` 3,600

Assume that days corresponding to interest of `150 are Y. Then 3,600 * Y/365 = ` 150

or , Y = 150*365/3600 = 15.2 days or 15 days (approx.)

Hence if X wants to save `150 by way of interest, he/she should pre-pone the payment of amount involved by 15 days from the average due date. 

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