Simple Interest

 Problem : 1 [ Simple Interest ]       Solve this type of problem 1. Find the simple interest on Rs 730 for 184 days at 25/4 % per annum. Show Answer A: Here P = Rs 730, R = 25/4 % and Time = 184 days = 184/365 years SI = (P*R*N)/100 = ( 730 * 25/4 * 184 /365) / 100 = 23Simple Interest is Rs 23 .

 Problem : 2 [ Simple Interest ]       Solve this type of problem 2. Find the simple interest on Rs 4660 for 5 years at 7/2 % per annum. Show Answer A: Here P =  Rs 4660, N = 5 years and R = 7/2 % SI = (P*R*N)/100 = ( 4660 * 7/2 * 5 ) / 100 = 815.5 Simple Interest is Rs 815.5 .

 Problem : 3 [ Simple Interest ]       Solve this type of problem 3. The interest on a certain amount of money at 8 % per year for a period of 4 years is Rs 512 . Find the sum of money. Show Answer A: Here SI = Rs 512, N = 4 years, R = 8 % SI = (P*R*N)/100P = (SI*100) / (R*N)P = (512 * 100 ) / ( 8 * 4 ) = 1600 The sum of money is Rs 1600 .

 Problem : 4 [ Simple Interest ]       Solve this type of problem 4. Simple Interest on Rs 972 at 14 % per annum for a certain time is Rs 476.28 . Find the time ? Show Answer A: Here P = 972, SI = Rs 476.28, R = 14%SI = (P*R*N)/100 N = (SI*100) / (P*R)N = ( 476.28 * 100 ) / ( 972 * 14 ) = 3.5 The time is 3.5 years

 Problem : 5 [ Simple Interest ]       Solve this type of problem 5. Simple Interest on Rs 972 at a certain rate % per annum for 3.5 years is Rs 476.28 . Find the rate ? Show Answer A: Here P = 972, SI =  Rs 476.28, N = 3.5SI = (P*R*N)/100R = (SI*100) / (P*N) = ( 476.28 * 100 ) / ( 972 * 3.5 ) = 14 The rate is 14 %.

 Problem : 6 [ Simple Interest ]       Solve this type of problem 6. A sum of money lent at simple interest amounts to Rs 1008 in 2 years and to 1112 in 3 years.Find the sum and the rate of interest. Show Answer A: Principal + Interest for 3 years = 1112 Principal + Interest for 2 years = 1008 => Interest for 1 year = 1112 - 1008 = 104 => Interest for 2 years = 2 * 104 = 208 Now, Principal + Interest for 2 years = 1008 => Principal + 208 = 1008 => Principal = 1008 - 208 = 800 SI = (P*R*N)/100R = (SI*100) / (P*N) = ( 208 * 100 ) / ( 800 * 2 ) = 13 The Sum of money is Rs 800 and the rate of interest is 13 %

 Problem : 7 [ Simple Interest ]       Solve this type of problem 7. What sum of money lent out at simple interest at 9 % p.a. for 3/2 years will produce the same interest as Rs 2250 lent at 6 % p.a. for 5 years. Show Answer A: Here P =  Rs 2250, N = 5 years, R = 6%SI = (P*R*N)/100SI = (2250 * 6 * 5 ) / 100 = 675 Now, SI =  Rs 675, N = 3/2 years, R = 9%SI = (P*R*N)/100P = (SI * 100) / (R * N) = ( 675 * 100) / ( 9 * 3/2 ) = 5000 The sum of money is Rs 5000

 Problem : 8 [ Simple Interest ]       Solve this type of problem 8. A man puts out Rs 500 for 4 years on simple interest and Rs 600 for 3 years. The total interest he receives is Rs 190 . What is the rate percent per annum? Show Answer A: Let the rate(R) % per annum = X SI on Rs 500 = (P*R*N)/100 = (500 * X * 4) / 100 = 20 X SI on Rs 600 = (P*R*N)/100 = (600 * X * 3) / 100 = 18 X Total SI = Rs 19020 X + 18 X = 190 38 X = 190 X = 190 / 38 = 5 Rate is 5 %

 Problem : 9 [ Simple Interest ]       Solve this type of problem 9. A sum was put at simple interest at a certain rate for 2 years. Had it been put at 3 % higher rate, it whould have fetched Rs 300 more. Find the sum. Show Answer A: Let sum = Rs X and original rate = R % Then,(X * ( R + 3 ) * 2)/100 - (X * R * 2)/100 = 300 2 R X + 6 X - 2 R X = 300 * 100 6 X = 300 * 100 X = 5000 The sum is Rs 5000 .

 Problem : 10 [ Simple Interest ]       Solve this type of problem 10. Divide Rs 16875 into two parts such that the interest at 7/2 % p.a. for 2 years on one part is equal to the other at 4 % p.a. for 5 years. Show Answer A: Let the Principal of one part = X RsThe Principal of second part = ( 16875 - X ) RsFor one part, P = X Rs, R = 7/2 %, N = 2 years SI = (P*R*N)/100SI = ( X * 7/2 * 2 ) / 100 = (7 * X)/100 ->(1)Now for second part, P = ( 16875 - X ) Rs, R = 4 %, N = 5 years SI = (P*R*N)/100SI = (( 16875 - X ) * 4 * 5 ) / 100 = (20 * ( 16875 - X ))/100 ->(2)Interest is the same as (1) = (2) => (7 * X)/100 = (20 * ( 16875 - X ))/100 => 7 X = 20 * ( 16875 - X ) => 7 X = 20 * 16875 - 20 X => 27 X = 20 * 16875 => X = (20 * 16875) / 27 => X = 12500 :.One part of Principal = Rs 12500 and the second part = Rs ( 16875 - 12500 ) = Rs 4375 The two parts are Rs 12500 and Rs 4375 .

 Problem : 11 [ Simple Interest ]       Solve this type of problem 11. A shopkeeper borrowed Rs 20000 from two money lendeRs For one loan he paid 12 % and for the other 14 % per annum. After 1 year, he paid Rs 2560 as interest. How much did he borrow at each rate ? Show Answer A: Let money at 12 % = X and that at 14 % = ( 20000 - X ) After one year total interest = 2560(X * 12 * 1) / 100 + ((20000 - X) * 14 * 1) / 100 = 2560 12 X + 14 * 20000 - 14 X = 2560 * 100 -2 X = -24000 X = 12000 :.Money at 12 % = Rs 12000 and Money at 14 % = Rs 8000 .

 Problem : 12 [ Simple Interest ]       Solve this type of problem 12. At what rate percent per annum will sum of money double in 8 years? Show Answer A: Let, Sum = X, Time = 8 years and Amount = 2X. :. SI = X. SI = (P*R*N)/100R = (SI * 100)/(P * N) = (X * 100)/( X * 8 ) = 25/2 % :. sum of money double at 25/2 % in 8 years.

 Problem : 13 [ Simple Interest ]       Solve this type of problem 13. Rajeev deposited money in the post office which is doubled in 20 years at a simple rate of interest. In how many years will the original sum triple itself ? Show Answer A: Let, Sum = X, Time = 20 years and Amount = 2X. :. SI = X. SI = (P*R*N)/100R = (SI * 100)/(P * N) = (X * 100)/( X * 20 ) = 5 % :. sum of money double at 5 % in 20 years.