simple interest Topic-wise Practice Test, Examples With Solutions & More Shortcuts

Simple Interest - Basic Formulas, Shortcuts, Rules, Tricks & Tips - Quantitative Aptitude

Useful For All Competitive Exams Like UPSC, SSC, BANK & RAILWAY

Posted By Careericons Team

Introduction to Simple Interest:

Interest is the sum which is paid for the use of other’s money. In other words, interest is the payment made for the money borrowed from banks or moneylenders. The money borrowed is called principal and the sum of the principal and interest is called amount.

The interest is usually paid yearly, half-yearly or quarterly as agreed upon. If it is payable yearly, it is called rate per cent per annum. For most problems involving interest, one year is taken as 365 days.

One month is taken as 30 days. When counting the number of days, the day of deposit is not counted, but the day of withdrawal is included. There are two types of interest: Simple and Compound.

When the interest on a certain sum borrowed for a certain period is reckoned uniformly, then it is called simple interest. Throughout the loan period, interest is charged on the original sum (principal) borrowed.

Important 7 Basic Formulae for solving all kinds of Simple Interest Based Aptitude Problems:

"13" - Important Aptitude Rules, Formulas & Quick Tricks to Solve Simple Interest Based Aptitude Problems

In this list of rules, you will get an idea that How to solve all different types & kinds of Simple Interest based aptitude problems asked in various competitive exams like UPSC, SSC, Bank, and Railway examinations at all levels.

By using this method, you can able to solve all problems from basic level to advanced level of questions asked based on Simple Interest in a faster approch.

Let's discuss the rules one by one with all Simple Interest Rules & Formulas with examples,

RULE 1 :

RULE 2 :

If there are distinct rates of interest for distinct time periods i.e.

Rate for 1st $t_1$ years → $R_1$%

Rate for 2nd $t_2$ years → $R_2$%

Rate for 3rd $t_3$ years → $R_3$%. Then,

RULE 3 :

If a certain sum becomes 'n' times of itself in T years on Simple Interest, then the rate per cent per annum is.

RULE 4 :

If a certain sum becomes $n_1$ times of itself at $R_1$% rate and $n_2$ times of itself at $R_2$% rate, then,

RULE 5 :

If Simple Interest (S.I.) becomes 'n' times of principal i.e.

RULE 6 :

If an Amount (A) becomes 'n' times of certain sum (P) i.e.

RULE 7 :

If the difference between two simple interests is 'x' calculated at different annual rates and times, then principal (P) is

RULE 8 :

If a sum amounts to $x_1$ in t years and then this sum amounts to $x_2$ in t yrs. Then the sum is given by

RULE 9 :

If a sum with simple interest rate, amounts to 'A' in $t_1$ years and 'B' in same $t_2$ years, then,

RULE 10 :

If a sum is to be deposited in equal instalments, then,

where T = no. of years, A = amount, r = Rate of Interest.

RULE 11 :

To find the rate of interest under current deposit plan,

where n = no. of months.

RULE 12 : If certain sum P amounts to Rs. $A_1$ in $t_1$ years at rate of R% and the same sum amounts to Rs. $A_2$ in $t_2$ years at same rate of interest R%. Then,

RULE 13 :

The difference between the S.I. for a certain sum $P_1$ deposited for time $T_1$ at $R_1$ rate of interest and another sum $P_2$ deposited for time $T_2$ at $R_2$ rate of interest is

Refer: Get all Topic-wsie Quantitative aptitude problems for upcoming competitive exams