Introduction
What is simple interest?
Simple interest is a quick and easy method of calculating the interest charge on a loan. Simple interest is determined by multiplying the daily interest rate by the principal by the number of days that elapse between payments.
Important Formulae :
1. Simple interest(S.I) = [latex]\frac{principal(P) \times rate(R) \times time(T)}{100}[/latex]
2. Principal(P) = [latex]\frac{100 \times Simple interest}{Rate \times time}[/latex]
3. Rate = [latex]\frac{100 \times Simple interest}{principal \times time}[/latex]
4. Time = [latex]\frac{100 \times Simple interest}{principal \times rate}[/latex]
5. Amount = Principal+ simple interest (or) Amount = P(1 + [latex]\frac{R \times T}{100} [/latex])
Simple Interest is one of important topic in Quantitative Aptitude Section. In Simple Interest Quiz 11 article candidates can find questions with answer. By solving this questions candidates can improve and maintain, speed, and accuracy in the exams. Simple Interest Quiz 11 questions are very useful for different exams such as IBPS PO, Clerk, SSC CGL, SBI PO, NIACL Assistant, NICL AO, IBPS SO, RRB, Railways, Civil Services etc.
Q1
What will be the simple interest on Rs. 80,000 at 16(2/3) % per annum for 9 months?
- A. 8,000
B. 9.000
C. 10.000
D. 11,000
We are given:
Principal = Rs. 80,000
Rate of interest = [latex]16 \frac {2}{3}[/latex]%
Time = 9 months
Rate of interest = [latex]16 \frac {2}{3} = \frac {50}{3}[/latex]%
Simple Interest = [latex]\frac {(P × R × T)}{100}[/latex]
Substituting the given values, we get
Simple Interest = [latex]\frac {80,000}{100} \times \frac {50}{3} \times\frac {3}{4} [/latex]
Simple Interest = Rs.10,000
Q2
Find the simple interest on Rs. 5000 at 6 % per annum for the period from 5th Feb to 19th April, 2015.
- A. 40
B. 50
C. 60
D. 70
We are given:
Principal = Rs. 5000
Rate of interest = 6 %
Time = 5th Feb to 19th April, 2015
First find the time period 5th Feb to 19th April, 2015
Feb = 28 – 5 = 23 days
March = 31 days
April = 19 days
Total days = 23 + 31 + 19 = 73 days
Convert days into years, by dividing it by 365
Time = [latex]\frac {73}{365} = \frac {1}{5}[/latex]
Simple Interest = [latex]\frac {(P × R × T)}{100}[/latex]
[latex]\frac {[5000 × 6 × (\frac {1}{5})]}{100} = Rs. 60[/latex]
Q3
Suresh borrows Rs. 10,000 for 2 years at 4 % p.a. simple interest. He lends it to Ramesh at 6 % p.a. for 2 years. Find his gain in this transaction per year.
- A. Rs. 150
B. Rs. 200
C. Rs. 400
D. Rs. 450
We have to calculate the gain in 2 years.
1) In case of Suresh
S.I [latex]\frac {1000 \times 4 \times 2}{100} = Rs. 800[/latex]
2) In case of Ramesh
S.I. [latex]\frac {1000 \times 6 \times 2}{100} = Rs. 1200[/latex]
Suresh has a pay a simple interest of Rs. 80 to the person from whom he borrowed Rs. 1000 and Ramesh has to pay Rs. 120 to Suresh.
Hence, gain in 2 years = 1200 – 800 = Rs. 400
But we are asked to find gain of Suresh per year. Therefore,
Gain in 1 year = [latex]\frac {400}{2}[/laterx] = Rs. 200
Q4
At what rate percent per annum will sum of money double in 20 years?
- A. 1.2%
B. 2%
C. 4%
D. 5%
Hint: If sum of money becomes (z times) in (T) years at simple interest, then rate of interest (R) can be calculated using the formula:
Rate of Interest (R) % = [latex]\frac {100 (Z-1)}{T} [/latex]
Here, principal amount is not given.
Hence, we can directly use the trick to calculate the rate of interest.
Rate of Interest (R) % =[latex]\frac {100 (2-1)}{20} [/latex]
Rate of Interest (R) %=5 % p.a.
Alternate solution
Let Principle = P, then S.I. = P
P = [latex]\frac {(P × R × T)}{100}[/latex]
R = [latex]\frac {(P × 100)}{P \times T} = \frac {100}{20} = 5% p.qa.[/latex]
Q5
John took a loan of Rs. 1500 with simple interest for as many years as the rate of interest. If he paid Rs. 540 as interest at the end of loan period, what was the rate of interest?
- A. 2%
B. 3%
C. 4%
D. 6%
Simple interest is same as the rate of interest.
Hence,
Rate of interest = R% and Time = R years
S.I. = [latex]\frac {(P × R × R)}{100}[/latex]
60 = [latex]\frac {(1500 \times {R}^{2}))}{100}[/latex]
[latex]15 {R}^{2} = 540[/latex]
[latex]{R}^{2} = 36[/latex]
R = 6%
Rate of Interest = 6 %