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Simple Interest


Important formulae and tricks and shortcuts of Simple Interest:

We are providing you Important Concepts and Tricks on Simple Interest which are usually asked in almost all competitive exams like IBPS, Govt. Exams and CAT and in quantitative aptitude of MNCs. Use these below given tricks to solve questions within minimum time. These tricks will be very helpful for your upcoming Competitive Exam.



1) SI = P x R x T/100
2) Principal = Simple Interest ×100/ R × T
3) Rate of Interest = Simple Interest ×100 / P × T
4) Time = Simple Interest ×100 / P × R
5) If rate of Simple interest differs from year to year, then
Simple Interest = Principal × (R1+R2+ R3…..)/100
The four variables in the above formula are:
SI=Simple Interest
P=Principal Amount (This the amount invested)
T=Number of years
R=Rate of interest (per year) in percentage


Some Tricks to Solve easily

Trick 1:

If a sum of money becomes “n” times in “T years” at simple interest, then the rate of interest per annum can be given be

pic 2



Trick 2:

If an amount P1 is lent out at simple interest of R1% per annum and another amount P2 at simple interest rate of R2% per annum, then the rate of interest for the whole sum can be given by

pic 3



Trick 3: A sum of money at simple interest n1 itself in t1 year. It will become n2 times of itself in (If Rate is constant)

 pic 4


Trick 4:

In what time will the simple interest be “n” of the principal at “r %” per annum:-

rt =n x 100

 Trick 5:

If a certain sum of money is lent out in n parts in such a manner that equal sum of money is obtained at simple interest on each part where interest rates are R1, R2, ... , Rn respectively and time periods are T1, T2, ... , Tn respectively, then the ratio in which the sum will be divided in n parts can be given by

pic 5

For solved problems on above formulas please visit below sections: