Quantitative Aptitude: Simple Interest/Compound Interest Set 03

Simple Interest/Compound Interest Questions IBPS PO, SBI PO, NIACL, NICL, LIC, Dena Bank PO PGDBF, BOI, Bank of Baroda and other competitive exams

1. If the C.I on certain sum at 20% rate of interest in 2yrs is 13200. Then find the simple interest on same sum at same rate of interest when time is 3yrs.
   A) Rs18,000
   B) Rs12,000
   C) Rs15,000
   D) Rs20,000
   E) Rs25,000
   
   View Answer

   Option A
   Solution:
   C.I for 2yrs = 20% = 1/5
   .    5 ……………….6
   .    5 ……………….6
   .  25 ………………36
   11/25 * 100 = 44%
   44% = 13200
   We need S.I = 20*3 = 60%
   1% = 300
   60% = 18,000
2. A sum of money becomes 6000 after 2yrs and 9000 after 4yrs. Find the sum?
   A) 3000
   B) 4000
   C) 4500
   D) 5000
   E) 3500
   
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   Option B
   Solution:
   A : B : C
   Note : when time is same then ratio uses to solve question. See below
   A : B = B : C
   X : 6000 = 6000 : 9000
   X = 4000
3. If a sum of Rs216 becomes 343 in 3yrs. Then find C.I on Rs43,200 in 3yrs at the same rate of interest?
   A) 20,000
   B) 25,000
   C) 24,400
   D) 25,400
   E) 26,000
   
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   Option D
   Solution:
   first we will find rate of interest
   Note : – root varies according to time, here Time is 3 yrs so
   (216)^1/3 : (343)^1/3
   6 : 7 – difference is 1. Now 1/6*100 = 16(2/3)%
   Now according to question C.I for 3 yrs
   16(2/3)% = 1/6 .         6 …………7
   .                        .         6 …………7
   .                        .         6 …………7
   216 − 343 = 127
   216 =43,200
   1 = 200
   127 = 25,400  
4. A sum of money invested at C.I double itself in 6yrs. At the same rate of interest it will amount to eight times of itself in how many years?
   A) 15yrs
   B) 12yrs
   C) 18yrs
   D) 10yrs
   E) 22yrs
   
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   Option C
   Solution:
   NOTE :- sum increase in C.I in a manner – 1 …2…4…8…16
   6      6      6 = 18 yrs  
5. A sum of money invested at S.I triple itself in 6yrs. At the same rate of interest it will amount to 9 times of itself in how many years?
   A) 24yrs
   B) 22yrs
   C) 18yrs
   D) 16yrs
   E) 25yrs
   
   View Answer

   Option A
   Solution:
   In Simple interest P become 3P, it means 2P Is interest.
   2P = 6
   P = 3
   To make 9P, 8P will be interest = 24yrs  
6. At a sum of Rs24000 a man charge C.I at 16(2/3)% rate of interest in 1st year and 14(2/7)% in 2nd year and 12.5% in 3rd year. Find the C.I?
   A) 15000
   B) 12000
   C) 18000
   D) 10000
   E) 22000
   
   View Answer

   Option B
   Solution:
    
7. A sum becomes 24200 in two years and 26620 in 3years. Find the sum?
   A) 20000
   B) 18000
   C) 16000
   D) 21000
   E) 23000
   
   View Answer

   Option A
   Solution:
   to find rate = 26620 – 24200/24200 * 100 = 10%
   24200 is an amount after 2yr.
   .   10…………….. 11
   .   10…………….. 11
   .  100……………..121 = 24200
   .    So 100 = 20000
8. Find the C.I on Rs12000, if the rate of interest is 20% and time is 2yrs and it is compounded half yearly?
   A) 5560
   B) 5558
   C) 5558.2
   D) 5569.2
   E) 5467.2
   
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   Option D
   Solution:
   note – in half yearly time – double, R.O.I – half
   R=10%, T = 4yrs
   12000
   1200 …1200 ….1200 ….1200
   .        …120    ….120   ….120
   .                     ….120   ….120
   .                     ….12     ….120
   .                                  ….12
   .                                  ….12
   .                                  ….12
   .                                  ….1.2
   .                                   5569.2
9. If the difference between C.I and S.I is Rs12400 with 10% rate of interest in 3yrs. Then find the sum?
   A) 300000
   B) 500000
   C) 400000
   D) 600000
   E) 200000
   
   View Answer

   Option C
   Solution:
   S.I in 3yrs = 10*3 =30%…C.I in 3yrs
   .    10 ………..11
   .    10 ………..11
   .    10 ………..11
   .    1000 – 1331 = 33.1%
   Difference = 33.1 % − 30% = 3.1%
   3.1= 12400
   100 = 400000
10. S.I on certain sum for 3years at any rate of interest is Rs225 while C.I on the same sum at the same rate for 2yrs is 153. Find the rate%?
    A) 5%
    B) 6%
    C) 4%
    D) 7%
    E) 8%
    
    View Answer

    Option C
    Solution:
    S.I for 1yr = 225/3 =75
    S.I for 2nd yr= 150
    S.I         75         75
    C.I                     3(153-150=3)
    3/75 * 100 = 4%