Answer :
Is it simple interest or compound interest ?
For the amount Rs 5, 750 - in how many years ? Let us say n years.
1. Simple interest case
Rs 6, 500 = P ( 1 + r * 3 )
Rs 5, 750 = P ( 1 + r * n )
750 = P * r * (3 - n)
6,500/5,750 = (1+3r)/ (1+n r)
6500 + 6500 n r = 5750 + 3 * 5750 * r
750 = r ( 1725 - 650 * n )
r = 30 / ( 69 - 26 n ) = rate of interest
P = 750 / [ (3-n) r ] = 25 (69 - 26 n) / (3-n)
2. If it is compound interest, then it is more difficult, with out knowing the number of years after which the amount is Rs 5, 750.
6,500 = P ( 1 + r )^3
5750 = P ( 1 + r)^n
6500 / 5750 = (1+r)^(3-n)
r = - 1 + [ 1/(3-n) ] * Log (650/575)
P = 6,500 / (1 +r )^3
For the amount Rs 5, 750 - in how many years ? Let us say n years.
1. Simple interest case
Rs 6, 500 = P ( 1 + r * 3 )
Rs 5, 750 = P ( 1 + r * n )
750 = P * r * (3 - n)
6,500/5,750 = (1+3r)/ (1+n r)
6500 + 6500 n r = 5750 + 3 * 5750 * r
750 = r ( 1725 - 650 * n )
r = 30 / ( 69 - 26 n ) = rate of interest
P = 750 / [ (3-n) r ] = 25 (69 - 26 n) / (3-n)
2. If it is compound interest, then it is more difficult, with out knowing the number of years after which the amount is Rs 5, 750.
6,500 = P ( 1 + r )^3
5750 = P ( 1 + r)^n
6500 / 5750 = (1+r)^(3-n)
r = - 1 + [ 1/(3-n) ] * Log (650/575)
P = 6,500 / (1 +r )^3