Simple Interest – Aptitude Questions and Answers
Simple Interest is an important topic in Quantitative Aptitude, which involves calculating the interest earned or paid on a principal amount over a specified period of time. This chapter is an essential part of many competitive exams, such as SSC and Bank exams, and can be challenging for some candidates. However, with this collection of Simple Interest Aptitude Questions and Answers and the right preparation and guidance, you can increase your confidence in tackling these questions and mastering this important concept.
Simple Interest Formula and Quick Tricks
- Simple Interest formula: SI = (PRT)/100, where SI is the Simple Interest, P is the Principal, R is the Rate of Interest per annum, and T is the Time period in years.
- To find interest for one year, divide the Rate by 100 and multiply by the Principal
- To find total interest, multiply interest for one year by the number of years
- To find the total amount, add Principal and Simple Interest
- To find the Principal, divide Simple Interest by (Rate * Time)
- To find the Rate, divide Simple Interest by (Principal * Time)
- To find Time, divide Simple Interest by (Principal * Rate)
- Amount formula: A = P*(1+R*T/100)
- Time formula: T = 100*(A/P-1)/R
Sample Questions on Simple Interest
Q1: What would be the annual interest accrued on a deposit of Rs. 10,000 in a bank that pays a 4 % per annum rate of simple interest?
Here, P = 10000, R = 4, T = 1
=> SI = P x R x T / 100
=> SI = 10000 x 4 x 1 / 100
=> SI = 400
Thus, the annual interest would be Rs. 400
Q2: A sum of money amounts to Rs. 28,000 in 2 years at 20 % simple interest per annum. Find the sum.
Here, A = 28000, T = 2, R = 20
=> A = P + SI
=> A = P + (P x R x T / 100)
=> A = P [1 + (R x T / 100)]
=> 28000 = P [1 + 0.4]
=> P = 28000 / 1.4
=> P = 20000
Thus, the required sum is Rs. 20,000
Q3: A man borrowed a certain sum of money at the rate of 6 % per annum for the first two years, 9% per annum for the next three years, and 14% per annum for the period beyond 5 years. If he pays a total interest of Rs. 22,800 at the end of 9 years, find the amount he borrowed.
Let the borrowed sum be P.
=> SI for first 2 years + SI for next 3 years + SI for next 4 years = 22800
=> (P x 6 x 2 / 100) + (P x 9 x 3 / 100) + (P x 14 x 4 / 100) = 22800
=> 95 P / 100 = 22800
=> P = 24000
Therefore, Borrowed sum = Rs. 24,000
Q4: At what annual rate of interest will a sum of money be thrice in 10 years?
Amount = Principal + SI
If the sum of money would be thrice the principal after 10 years, the SI would be twice the principal.
=> SI = 2 x P
=> (P x R x T / 100) = 2 X P
=> R x T / 100 = 2
=> R x T = 200
=> R x 10 = 200
=> R = 20 %
Thus, the required rate of interest is 20 %
Q5: The simple interest on a sum of money in 5 years at 12 % per annum is Rs. 400 less than the simple interest accrued on the same sum in 7 years at 10 % per annum. Find the sum.
Let the sum be P.
=> SI in 5 years at 12 % per annum = P x 12 x 5 / 100 = 0.6 P
=> SI in 7 years at 10 % per annum = P x 10 x 7 / 100 = 0.7 P
Now, according to the question,
0.7 P – 0.6 P = 400
=> 0.1 P = 400
=> P = 4000
Thus, the required sum is Rs. 4000
Q6: A sum of Rs. 1000 was lent to two people, one at the rate of 5 % and the other at the rate of 8 %. If the simple interest after one year is Rs. 62, find the sum lent at each rate.
Let the sum lent at 5 % be P.
=> Sum lent at 8 % = 1000 – P
Now, according to the question,
SI for 5 % + SI for 8 % = 62
=> (P x 5 x 1 / 100) + ((1000 – P) x 8 x 1 / 100) =62
=> 5 P + 8 (1000 – P) = 6200
=> 5 P + 8000 – 8 P = 6200
=> 3 P = 1800
=> P = 600
Therefore, sum lent at 5 % = P = Rs. 600
Sum lent at 8 % = 1000 – P = Rs. 400
Test your knowledge of Simple Interest in Quantitative Aptitude with the quiz linked below, containing numerous practice questions to help you master the topic:
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