# Aptitude - Compound Interest - Discussion

### Discussion :: Compound Interest - General Questions (Q.No.6)

6.

What will be the compound interest on a sum of Rs. 25,000 after 3 years at the rate of 12 p.c.p.a.?

 [A]. Rs. 9000.30 [B]. Rs. 9720 [C]. Rs. 10123.20 [D]. Rs. 10483.20 [E]. None of these

Answer: Option C

Explanation:

Amount
 = Rs. 25000 x 1 + 12 3 100
 = Rs. 25000 x 28 x 28 x 28 25 25 25
= Rs. 35123.20

C.I. = Rs. (35123.20 - 25000) = Rs. 10123.20

 Viplov said: (Jun 19, 2010) Please give me a shortcut methods for competitive exams.

 Dayal said: (Feb 10, 2011) Pl send me the short cut method for compound interest calculation specially for more than 2 years.

 Deepak said: (May 18, 2011) Sir please send me any shortcut method for this question.

 Snehal said: (Sep 8, 2011) What is meaning of p.c.p.a ?

 Sujatha said: (Oct 31, 2011) What is the meaning of PCPA?

 Yogendra said: (Jan 14, 2012) Hi, sujatha & snehal PCPA means percentage per annum

 Sitam said: (Apr 3, 2012) Can any one know its simplest method to find out C. I.

 Sugi said: (Apr 17, 2012) Can any one explain me how 28 /25 came?

 Famitha said: (Aug 2, 2012) @Sugi. 28/25 is fraction if you directly divide 1+12/100 you will get 1.12. The cube of 1.12 is 1.404928.

 Selva said: (Oct 29, 2012) Hi friends, don't use any formulas for calculating compound interest. Here I show a simple way for all. Lets the principal amount be 25,000 rs here and time=3 years, rate of interest=12%. Firstly calculate the interest for 1 year==>25000*(12/100)=3000rs, So if we want to find the compound interest in second year firstly just add the interest amount to the principal amount==>25000+3000=28000rs. Then compound interest in 2 years=28000*(12/100)=3360rs,this is the compounded interest in 2 years..then now we just add the previous principal and interest calculated now..28000+3360=31360rs this is the principal amount now.. compounded interest in 3rd year=31360*(12/100)=3763.2rs. So compounded interest for this amount and rate of interest after 3 years=3000+3360+3763.2=10123.20rs. Does this concept of compound interest is understandable are not?

 Suresh said: (Jan 7, 2013) This method help us to easily understand the sum. Compound interest + sum of Rs.25000 = 25000 (1 + 12/100) ^3. =25000 (28/25) ^3. =35123.2. We needed only for compound interest =35123.2 - sum of Rs.25000. =35123.2 - 25000. =10123.2.

 Thanuja said: (Jun 22, 2013) Please send me the short cut method for compound interest calculation specially for more than 2 years.

 Pulkit said: (Jan 17, 2014) Anybody explain how comes 28/25*28/25*28/25 ?

 Ashok said: (Jul 22, 2014) Firstly simplify the 12/100 it will come 3/25 after that you will get 28/25.

 Sreenu said: (Aug 7, 2014) Using percentages Shortcut method for C.I when P, R%, time is given to find out CI: 1st year:-10% of 25000+2% of 25000=2500+250*2=2500+500 = 3000. 2nd year:-10% of 28000+2% of 28000=2800+280*2=2800+560 = 3360. 3rd year:_10% of 31360+2% of 31360=3136+313.6*2=3136+627.2 = 3763.2. So total interest is=3000+3360+3763.2 = 10123.2. I hope this method understand. Goodluck.

 Kasinath @Hyd said: (Aug 15, 2014) P.C.P.A means Percentage Compound Per Annum.

 Ashwini said: (Jan 13, 2015) I did not understand 2nd and 3rd step in explanation (28/25) how it come please send me details about this steps.

 Gayathri said: (Jan 15, 2015) Please I want a accurate method for 28/25.

 Anand Singh said: (Feb 7, 2015) Shortcut: P = 25000, T = 3 years. And R = 12 pcpa, C.I = ? C.I = 12% of 25000 = 3000. 12% of 3000 = 360. 12% of 360 = 43.20. i.e 3(3000) + 3(360) + 43.2 = 9000+1080 +43.20 = 10123.20 (since time = 3 years).

 Manoj said: (Jun 18, 2015) Here I got a method of solving compound interest for two years and three years. You just need to know SQUARES and CUBES to solve them in mind, without any pen and paper. I suppose if we know rate of interest collectively for two years or three years, it would be easy to find the interest. So here is d simple trick to find rate of interest 2 years: If rate of interest is given. 10% ==> 10+10+1^2 = 21. So 21 is the rate of interest for two years collectively. @10pcpa interest. 20% ==> 20+20+2^2 = 44. 30% ==> 30+30+3^2 = 69. 12% ==> 12+12+1. 2^2= 25. 44. Hope it's understandable. Now for 3 years: 10% ==> 10+10+10+1^2+1^2+1^2+1^3/10. ==>30+1+1+1+1/10. ==>33+0.1=33.1. So, @10% per annum the compounded interest for three years it will b 33.1%. If it's 5% per annum then, 5% ==> 5+5+5+0.5^2+0.5^2+0. 5^2+0.5^3/10. ==>15+0.25+0.25+0.25+0.125/10. ==> 15.75+0.0125 = 15.7625%. I hope it's helpful n understandable.

 B M Vinutha said: (Aug 6, 2015) Dear sir/madam, Please calculate the compound interest on rs 25000 for first 2 years @15% and @16%for 3rd year.

 Muneer said: (Jan 12, 2016) Please explain how come 28/25?

 Jhumu Chakrabortty said: (Jan 25, 2016) Why we are not taking minus 1 in the formula for compound interest?

 Suneesh V said: (Feb 27, 2016) A sum of money lent at compound interest amount to Rs. 1210 in two years and to rupees 1464.10 in 4 years find the rate of interest.

 Palani said: (Aug 26, 2016) How comes 28/25 * 28/25 * 28/25?

 Sony Kumari said: (Oct 22, 2016) Can anyone explain it in short method?

 Viki said: (Jan 12, 2017) Good method @Selva. Thanks for posting it.

 Mohan said: (May 10, 2017) @Snehal and @Sujata. p.c.p.a means per capital per annum.

 Sankari said: (May 22, 2017) Please explain how 28/25 came?

 Sivasankari said: (May 22, 2017) @Muneer. = 25000 * (1+12/100) => 250009112/100)^3. = 25000(56/50)^3. = 25000(28/25)^3. And now expand the cube root we get 25000 * 28/25 * 28/25 * 28/25.

 Ashish Jadhav said: (Jul 14, 2017) (1+12/100) = 1 * 100 + 12/100 = 100 + 12/100 = 112/100 = 28/25. It is cross multiplication.

 Ashish Jadhav said: (Jul 14, 2017) It is cross multiplication. (1+12/100). = (1*100+12)/100, = (100+12)/100, = 112/100, = 28/25 i.e. divided by 4.

 Amit said: (Oct 31, 2017) 12% = 12/100 = 3/25. p = 25000. Solve --- 25000x3/25 = 3000 first interest. 1st = 3000. 2nd = 3000 + 360. (3000x3/25=360). 3rd = 3000 + 360 + 360 + 43.20. (360x3/25=43.20). -------------------------------------- 9000+720+360+43.20 = 10123.20. Its answer are exactly correct. Sort and best math any Question solve in 15 second any problem.

 Budhlani Badshah said: (Jul 24, 2018) @Amit. Thank you for the best explanation.

 Bhaskar Chakrabarty said: (Oct 1, 2018) What will be the rate of compound interest if a man invests Rs. 1, 01, 490 and get Rs. 2, 03, 500 after 10 years? Can anyone answer it?

 Kj B Vinothan said: (Jan 27, 2020) Rate interest 12 for 3 year. 1st 2 year =a+b+(a*b/100)=12+12+(12*12/100)=25.44%. 3rd year = 25.44+12+(12*25.55/100)=40.49%. Then substitute the r value in simple interest for 1 year then you can get answer directly.

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