Simple interest Time in Month and Days

Recap on simple interest Amount = Principal + Interest Where n is in years

Some example where period (n) is not in years 1) Period=14 months. In a year there are 12 months , so period as a fraction of year is (after simplifying) 2) Period=200 days. In a year there are 365 days, so period as a fraction of year is (after simplifying) 3) Period from 4th Oct 2017 to 11th Dec 2017. We need to find the number of days between the given dates Oct=31 days – 3 days (except days from Oct 1 to Oct 3 ) =28 days Nov=30 days (whole month) and Dec = 10 days (from Ist to 10th Dec) Total days = 28 + 30 + 10 = 68 days. So period as fraction of years is

Example 1: Find the simple interest due on Rs Example 1: Find the simple interest due on Rs. 3,750 for 73 days at 5 % per annum. Solution: Given: p= 3750 , r= 5 n= To find : Simple interest Ans: I = Rs. 375

Example 2: Lokesh invested Rs 2,400 in a bank that pays an interest of 7 % per annum. He withdraws the amount after 2 years and 5 months. Find the interest, he receives. Solution Given: Principal(P)=2400 , Rate(r)=7% per year , Period(n)=2 year 5 months. To find : Simple Interest(I) Period(n) is not completely in year so lets convert it to year n = 2 year 5 months Convert month part as fraction of year Ans: Interest (I) = Rs 406

Example 3: Find the S.I and amount on Rs 12,000 from May 21st 1999 to August 2nd 1999 at 9 % per annum. Solution: Given:- P = Rs 12000, Rate 9% per annum Period from May 21st 1999 to August 2nd 1999 To find : Simple Interest(I) We need to find the number of days between the given dates May 21st 1999 to August 2nd 1999 May=31 days – 20 days =11 days (except days from May 1 to May 20 ) June=30 days (whole month) July=31 days (whole month) August = 1 day (1st Aug ) Total days = 11+ 30 + 31 + 1 = 73 days. So period as fraction of years is

Ans : Simple interest = Rs 216 2 4 I = 2 4 x 9 I = 216 Ans : Simple interest = Rs 216

Try these 1. Find S.I. and amount on Rs 3,600 at 15% p.a. for 3 years and 9 months. 2. Find the simple interest on Rs.7300 for 180 days at 10 % per year.