Tips And Tricks And Shortcuts For Simple Interest Problems

Tips & Tricks and Shortcuts for Simple Interest

Simple Interest= P*R*T/100

  • Simple interest is calculated by multiplying the daily interest rate by the principal by the number of days that elapse between payments.

Here, are quick and easy tips and tricks on Simple Interest problems learn easily tricks and tips on SI and efficiently in competitive exams and recruitment drive process.

There are mainly 2 types of questions asked in exams. However, these questions can be twisted to check the students’ understanding level of the topic. 

Simple Interest_tips and tricks

Simple Interest Tricks and Tips and Shortcuts.

  • 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: √(100/x)
  • The rate of interest for t1 years is r1%, t2 years is r1%, t3 years is r3 %. If a man gets interest of Rs x for (t1+ t2 + t3 = n)  years, then principal is given by:
    (x*100)/r1t1 + r2t2 + r3t3
  • If sum of money becomes x times in t years at simple interest, then the rate is calculated as R = 100 (x-1)/t %
  • If a sum of money becomes x times in t years at simple rate of interest, then the time is calculated as t = 100 (x-1)/R
  • If an amount P1 is lent out at simple interest of R1% p.a. and another amount of P2 at simple interest of R2% p.a, then the rate of interest of the whole sum is given by: R = (P1R1 + P2R2)/P1+P2


Type 1: Tips and Tricks and Shortcuts To Find Simple Interest

Question 1.

Find the simple interest of Rs 1000 for 10 years at 6% p.a.?


A. Rs. 60

B. Rs. 6000

C. Rs. 600

D. Rs. 6


We know that, SI = p*r*t/100

SI = 1000*6*10/100

SI = 60000/100

SI = Rs. 600

Correct option: C

Type 2: Simple Interest Tips and Tricks- When Rate of Interest is different for Different Years

Question 1.

If a sum of Rs.25000 is given as loan for a period of 4 years with the interest rates 2%, 4%, 5%, and 6% for the 1st, 2nd, 3rd, and 4th year respectively. What is the total amount that has to be paid at the end of 4 years?


A. Rs. 29250

B. Rs. 29520

C. Rs. 25920

D. Rs. 25290


As this is a case of Simple Interest we add 2% + 4% + 5% and 6% = 17%.

Amount = Principal + Rate of Interest.

Principal is 100% of the amount. 

Amount = 100% + 17%.
Therefore Amount = 117%

Amount = (117*25000)/100


Correct option: A

Type 3: Simple Interest Tips and Tricks and Shortcuts To find the (Rate of Interest, Time period, Principal)

Question 1.

A sum of money becomes 5 times in 20 years. Calculate the rate of interest.


A. 20%

B. 13%

C. 15%

D. 25%


We know that, If sum of money becomes x times in t years at simple interest, then the rate is calculated as R = 100 (x-1)/t %

R = 100 (5-1)/20 

R = 100 (4)/20

R = 400/20

R = 20%

Correct option: A

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