# Simple Interest Test Solved Questions and Answers

Posted On:February 28, 2019, Posted By: Latest Interview Questions, Views: 1950, Rating :     ## Best Simple interest questions and answers for competitive exams

Dear Readers, Welcome to Simple Interest - Aptitude Objective Questions have been designed specially to get you acquainted with the nature of questions you may encounter during your Job interview for the subject of Simple Interest - Aptitude MCQs. These objective type Simple Interest - Aptitude questions are very important for campus placement test and job interviews. As per my experience good interviewers hardly plan to ask any particular question during your Job interview and these model questions are asked in the online technical test and interview of many Banks, SSC, Railways, Postal and many Govt Jobs. ## Simple Interest Important Formulas

1. Principal :

The money borrowed or lent out for a certain period is called the principal or the sum.

2. Interest :

Extra money paid for using other’s money is called interest.

3. Simple Interest (S.I.) :

If the interest on a sum borrowed for certain period is reckoned uniformly, then it is called simple interest.

Let the principal = P, Rate = R% per annum (p.a) and Time = T years. Then ,

1. S.I. = (P x R x T / 100)

2. P = (100 x S.I. / R x T)

3. R = (100 x S.I / P x T)

4. T = (100 x S.I. / P x R).

## Simple Interest Solved example Problems

### 1. At what rate percent per annum will a sum of money double in 16 years?

Explanation:

Let principal = P. Then, S.I. = P and T = 16 years

=> Rate = [100 * P / P * 16]%

= 6 1/4% p.a

### 2. The simple interest on a sum of money is 4/9 of the principal. Find the rate percent and time, if both are numerically equal.

Explanation:

Let sum = Rs. x Then, S.I. = Rs. 4x/9

Let rate = R% and time = R years.

Then, [x * R * R / 100] = 4x / 9 or R² = 400/9 or R = 20/3 = 6 2/3

=> Rate = 6 2/3 % and Time = 6 2/3 yrs

= 6 yrs 8 months.

### 3. A sum was put at simple interest at a certain rate for 3 years. Had it been put at 2% higher rate, it would have fetched Rs. 360 more. Find the sum.

Explanation:

Let sum = P and original rate = R. Then,

[P * (R+2) * 3 / 100] - [P * R * 3 / 100] = 360

=> 7x/20 - 3x/10 = 40

=> x = (40 * 20) = 800.

Hence, the sum is Rs. 800.

### 4. Find the simple interest on Rs. 68,000 at 16 2/3 % per annum for 9 months.

Explanation:

Let sum = P and original rate = R. Then,

[P * (R+2) * 3 / 100] - [P * R * 3 / 100] = 360

=> 7x/20 - 3x/10 = 40

=> x = (40 * 20) = 800.

Hence, the sum is Rs. 800.

### 5. Reena took a loan of Rs. 1200 with simple interest for as many years as the rate of interest. If she paid Rs. 432 as interest at the end of the loan period, what was the rate of interest?

Explanation:

Let rate = R% and time = R years. Then

(1200 x R x R / 100) ‹=› 432

‹=›12R2 = 432

‹=›R2 = 36

‹=› R = 6

## Simple Interest Exercise Problems and Answers

### 1. At the rate of 6% p.a. simple interest, a sum of Rs. 2500 will earn how much interest by the end of 5 years 7.

A. Rs. 150

B. Rs. 750

C. Rs. 700

D. Rs. 3250

Explanation:

2500 * (3 * (5/100)) =750

### 2. A sum of Rs. 800 amounts to Rs. 920 in 3 years at simple interest. If the interest rate is increased by 3%, it would amount to how much?

A.764

B.992

C.850

D.770

Explanation:

S.I = Rs. (920 – 800) = Rs. 120; P = Rs. 800, T = 3 yrs

R = ( 100 X 120 )% / 800 X 3 = = 5%

New rate = (5 + 3) % = 8%

New S.I. = Rs. (800 X 8 X 3)/ 100== Rs. 192.

New amount = Rs. (800 + 192) = Rs. 992

### 3. A sum of money at simple interest amounts to Rs. 815 in 3 years and to Rs. 854 in 4 years. The sum is:

A.650

B.690

C.698

D.700

Explanation:

S.I. for 1 year = Rs. (854 – 815) = Rs. 39

S.I. for 3 years = Rs. (39 x 3) = Rs. 117

Principle = Rs. (815 – 117) = Rs. 698

### 4. The price of a T.V set worth Rs. 20,000 is to be paid in 20 installments of Rs. 1000 each. If the rate of interest be 6% per annum, and the first installment be paid at the time of purchase, then the value of the last installment covering the interest as well will be:

A.1050

B.2050

C.3000

D.5000

E.None of these

Explanation:

Money paid in cash = Rs. 1000.

Balance payment    = Rs. (20000 – 1000)

= Rs. 19000.

### 5. A sum of money is lent at S.I for 8 years. If the same amount is paid at 5% higher, Ramesh would have got Rs. 100 more. Find the Principal?

A.200

B.240

C.250

D.300

Explanation:

Let the Principal be P Rs.

Let the first rate of interest be r

The difference in r is 5

5 x P x N = (Difference in interest) x 100

5 x P x 8 = 100 x 100

p = 100 x 100 / 5 x 8

= Rs. 250

### 6. If simple interest on a certain sum of money for 4 years at 5% per annum is same as the simple interest on Rs. 560 for 10 years at the rate of 4% per annum then the sum of money is:

A.1190

B.1120

C.1210

D.1280

Explanation:

Let the required sum of money be Rs. X.

Here R1 = 5%, T1 = 4 years, R2 = 4%, T2 = 10 years.

Given  X : 560 = 1 / R1T1 : 1 / R2T2 :

= 1 / 5X4 : 1 / 4X10

X = 2 or, X = Rs. 1120.

### 7. A sum fetched a otal simple interest of Rs. 4016.25 at the rate of 9 p.c.p.a. in 5 years. What is the sum?

A. 8925

B. 8259

C. 8529

D. 8952

Ans: A

Explanation:

Principal = Rs. [100 * 4016.25 / 9 * 5]

= Rs. [401625 / 45]

= Rs. 8925.

### 8. A sum of money at simple interest amounts to Rs. 815 in 3 years and to Rs. 854 in 4 years. The sum is:

A. 500

B. 698

C. 780

D. 910

Ans: B

Explanation:

S.I. for 1 year = Rs. (854 - 815) = Rs. 39.

S.I. for 3 years = Rs. (39 * 3) = Rs. 117.

Principal = Rs. (815 - 117)

= Rs. 698.

### 9. How long will it take a sum of money invested at 5% p.a. S.I. to increase its value by 40%?

A. 6 years

B. 7 years

C. 8 years

D. 9 years

Ans: C

Explanation:

Let the sum be x. Then, S.I. = 40% of x = 2x/5; Rate = 5%.

Time = [100 * 2x/5 * 1/x*5]

= 8 years.

### 10. A sum of money lent out at simple interest amounts to Rs. 720 after 2 years and to Rs. 1020 after a further period of 5 years. The sum is

A.  Rs. 500

B.  Rs. 600

C.  Rs. 700

D.  Rs. 710

Ans: B

Explanation:

S.I. for 5 year = Rs.(1020 - 720)

= Rs. 300.

S.I. for 2 year = Rs.(300/5×2)

= Rs. 120.

Principal = Rs. (720 - 120)

= Rs. 600.

### 11. How much time will it take for an amount of Rs. 450 to yield Rs. 81 as interest at 4.5% per annum of simple interest?

A.  3.5 years

B.  4 years

C.  4.5 years

D.  5 years

Ans: B

Explanation:

Time = (100×81/ 450×4.5)years

= 4 years.

A. 3%

B. 4%

C. 5%

D. 6%