# Simple Interest Questions

FACTS  AND  FORMULAE  FOR  SIMPLE  INTEREST  QUESTIONS

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 a certain period is reckoned uniformly, then it is called simple interest.

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

(i)  $S.I=\left(\frac{P×T×R}{100}\right)$

(ii)

Q:

The simple interest on Rs. 25 for 4 months at the rate of 3 paise per rupee per month is :

 A) 240 paise B) Rs. 1.40 C) Rs. 2.20 D) Rs. 3

Explanation:

I = PTR/100
I = 25 x 4 x 0.03/100
I = 0.03 x 100 = 300 Ps = Rs. 3

23 13451
Q:

What is the principal sum?
I. The sum amounts to Rs. 690 in 3 years at S.I.
II. The sum amounts to Rs. 750 in 5 years at S.I.
III. The rate of interest is 5% p.a.

 A) I and III only B) II and III only C) I and II only D) Any two of the three

Explanation:

Clearly, any of the three will give us the answer

11 12991
Q:

A sum at simple interest at $1312$% per annum amounts to Rs. 2502.50 after 4 years. Find the sum

 A) Rs.1625 B) Rs1525 C) Rs.1425 D) Rs.1325

Explanation:

Let sum be Rs.x then, S.I. =Rs. [ x * (27/2) * 4 * (1/100) ] = Rs. 27x/50

Amount =Rs [ x + (27x/50)] = Rs.77x/50

=> 77X/50 = 2502.50

=>X= (2502.50 * 50)/77 = 1625

Hence Sum = Rs.1625

11 12705
Q:

What will be the ratio of simple interest earned by certain amount at the same rate of interest for 6 years and that for 9 years?

 A) 1:3 B) 1:4 C) 2:3 D) data is inadequate

Explanation:

Let the principal be P and rate of interest be R%.

Required ratio =$P*R*6100P*R*9100=6PR9PR=69=23$

14 12570
Q:

The simple interest on a sum of money will be Rs.600 after 10 years. If the principal is trebled after 5 years what will be the total interest at the end of the tenth year ?

 A) Rs. 1100 B) Rs. 1200 C) Rs. 1000 D) Rs. 1840

Explanation:

P --- 10 ----- 600

P --- 5 ----- 300

3P --- 5 ----- 900
__________
1200

25 12233
Q:

The simple interest on Rs.10 for 4 months at the rate of 3 paise per month is

 A) 0.3 Paise B) 1.2 Paise C) 30 Paise D) 3 Paise

Explanation:

Given Principal amount P = Rs. 10

Time T = 4 months

Rate of interest R = 3 ps

Interest I = PTR/100 = (10 x 4 x 3)/100 = 12/10 = 1.2 paise.

6 11964
Q:

1. The simple interest on a sum of money is Rs. 50. What is the sum?
I. The interest rate is 10% p.a.
II. The sum earned simple interest in 10 years

 A) I alone sufficient while II alone not sufficient to answer B) II alone sufficient while I alone not sufficient to answer C) Either I or II alone sufficient to answer D) Both I and II are necessary to answer

Explanation:

Given : S.I. = Rs. 50.

I  gives,  R = 10% p.a.

II gives,  T = 10 years.

Sum = (100 x S.I)/(t x r ) =  Rs.(100 x 50)/(10 x 10) = Rs.50

5 11708
Q:

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