Simple Interest

 Simple Interest

Simple Interest = P*R*N/100

Here, P = Principal,

         R = Rate of Interest (%)

         N = Number of Years.

        SI = Simple Interest

If we want to find the P (Principal)

P = (SI*100) / (R*N)

If we want to find the R (Rate of Interest)

R = (SI*100) / (P*N)

If we want to find the N (Number of Years)

N = (SI*100) / (R*P)

Amount = P + SI

Example : Find Simple Interest on Rs. 1500 at 18% per Annum for 3 years.

Solution : Here, P = 1500, R = 18%, N = 3 Year. 

                 SI = P*R*N/100

                     = (1500*18*3)/100

                     = 800

Example : Find Simple Interest on Rs. 1600 at 7.5% per Annum for 2 years and 4 months.

Solution : Here, P = 1600, R = 7.2%= (15/2)%, N = 2Years 4Months = 28/12 year. 

                 SI = P*R*N/100

                     = (1600*15*28)/(100*12*2)

                     = 280

Example : Find the amount of Rs. 1400 invested at 14% during the from 5th February 1994 to 19th April 1994.

Solution : Here, P = 1400, R = 14%, N = 73/365 year. 

                 SI = P*R*N/100

                     = (1400*14*73)/(100*365)

                     = 39.2

                  Amount = P + SI

                                = 1400 + 39.2

                                = 1439.2

Example : If Rs.64 amount  to Rs.83.20 in 2 years, What will Rs.86 amount to in 4 years at the same Rate per annum?

Solution : We have Amount = 83.20, P = 64 , N = 2 Year

                    So, SI = Amount - P

                          SI = 83.20 - 64

                          SI = 19.20

                           R = (SI*100) / (P*N)

                           R = (19.20*100) / (64*2)

                           R = 15%

Now  We have to find the SI  for 4 year So, N = 4 Year

                          SI = P*R*N/100

                               = (86*15*4)/(100)

                               = 51.6

            So Amount = P + SI 

                               = 86 + 51.6

                               = 137.6