# Simple Interest Tricks

This topic easily plays an important role in scoring marks in Bank, Railway, SSC exams as you only have to do simple calculations by applying the shortcut tricks. Generally, there are about 1-2 questions in the question paper from this topic and the difficulty level depends on the exam whether it is Bank, Railway, SSC or any other exam. Regular practice of various types of questions using Simple Interest Tricks (साधारण ब्याज ट्रिक्स) will also help you to save time in the exam.

Interest: When a person borrows money from another person or bank, the rent he has to pay to use the money of another person or bank is called interest.

Simple Interest (साधारण ब्याज): If the interest on a sum borrowed for certain period is calculated uniformly, it is called simple interest (SI).

Principal (Sum): Principal (or the sum) is the money borrowed or lent out for a certain period. It is denoted by P.

Amount: The Addition of Simple Interest and Principal is called the Amount.

Time: This is the duration for which money is lend / borrowed.

Rate of Interest: It is the rate at which the interest is charge on principal.

 Simple Interest Formula (साधारण ब्याज फार्मूला)

Where, P = Principal Sum (the original loan/ deposited amount)

R = rate of interest (at which the loan is charged)

T = time period (the duration for which money is borrowed/ deposited)

Amount (A) = Principal (P) + Simple Interest (SI)

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## Useful Simple Interest Tricks (साधारण ब्याज ट्रिक्स)

 Trick 1

If the interest on a sum of money is 1/x of the principal, and the number of years is equal to the rate of interest then rate can be calculated using the formula:

Example: The interest on a sum of money is 1/16 of the principal, and the number of years is equal to the rate of interest. What is the rate percent?

Solution:

Example: The simple interest on a sum of money is 1/9 of the principal and the number of years is equal to the rate % p.a. The rate % p.a. is?

Solution:

 Trick 2

If the sum is put at SI at a certain rate r1 % for t1 years, again at r2 % for t2 years and then so on, then

Example: The rate of interest for 3 years is 4%, 5 years is 6%, 1 year is 5%. If a man gets interest of Rs. 4700 for 9 years, calculate the principal amount?

Solution:

Example: The rate of interest for the first 2 years is 3% per annum, for the next 3 years is 8% per annum and for the period beyond 5 years 10% per annum. If a man gets Rs. 1520 as a simple interest for 6 years, how much money did he deposit?

Solution:

Check Here – How to Prepare Maths for Competitive Exams

 Trick 3

If a person deposits Rs. x1 in a bank at r1 % per annum and Rs. x2 in another bank at r2 % per annum, then the rate of interest for the whole sum is

Example: A man deposits Rs. 1350 in a bank at 5% per annum and Rs. 1150 in another bank at 6% per annum. Find the rate of interest for the whole sum.

Solution:

Example: A man deposits Rs. 4000 in a bank at 15% per annum and Rs. 6000 in another bank at 16% per annum. Find the rate of interest for the whole sum.

Solution:

 Trick 4

If a sum of money becomes ‘x’ times in ‘n’ years at simple rate of interest, then the rate is calculated as

Example: A sum of money becomes 4 times in 20 years. Calculate the rate of interest.

Solution:

Example: A sum becomes 2 times at simple interest in 10 years. What is the rate of interest?

Solution:

Also Check – Maths Formulas

 Trick 5

If a sum of money becomes ‘n’ times in ‘t’ years at a simple interest, then the time in which it will amount to ‘m’ times itself is given by

Example: A sum of money becomes 5 times itself in 5 years at a simple interest. In how many years will it amount to 7 times itself?

Solution:

Example: A certain sum of money triples itself in 5 years at simple interest. In how many years it will be five times?

Solution: