Quantitative Aptitude: Simple/Compound Interest Set 07

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

1. Mosses invested Rs. 20,000 in a scheme at simple interest @ 15% per annum. After three years he withdrew the principal amount plus interest and invested the entire amount in another scheme for two years, which earned him compound interest @ 12% per annum. What would be the total interest earned by Mosses at the end of 5 years?
   A) Rs. 16377.6
   B) Rs. 10152.3
   C) Rs. 11012.14
   D) Rs. 12500
   E) None
   
   View Answer

   Option A
   Solution:
   SI= 20,000*15*3/100=9000
   Amount=20,000+9000=29,000
   Now CI= 29,000*(1+12/100)² = 29,000 * 28/25 * 28/25 = 36,377.6
   A-P=36, 377.6-29000=7377.6
   After 5yrs 7377.6+9000=16,377.6
2. A certain sum is invested for certain time. It amounts to Rs. 600 at 10% per annum. But when invested at 5% per annum, it amounts to Rs. 400. Find the time.
   A) 40 years
   B) 75 years
   C) 50 years
   D) 60 years
   E) None
   
   View Answer

   Option A
   Solution:
   600-P=P*10*t/100 —>1===>6000-10P=Pt
   400-P=P*5*t/100—->2===>8000-20P=Pt
   Equate 1 and 2 6000-10P=8000-20P==>P=200
   Substitute P in 1 then 400=200*5*t/100==>40yrs.
3. A lent Rs. 8000 to B for 2 years and Rs 6000 to C for 4 years on simple interest at the same rate of interest and received Rs 1840 in all from both of them as interest. The rate of interest per annum is
   A) 4.6%
   B) 8.4%
   C) 6.3%
   D) 10%
   E) None
   
   View Answer

   Option A
   Solution:
   rate of interest be r%
   Then
   8000*2*R/100 + 6000*4*R/100 = 1840
   160R+240R = 1840
   400R = 1840
   R = 4.6 % p.a 
4. A Man lends Rs. 1540 for five years and Rs. 1800 for four years. If he gets Rs. 1788 as interest on both amounts, what is the rate of interest ?
   A) 10%
   B) 12%
   C) 15%
   D) 8%
   E) None
   
   View Answer

   Option B
   Solution:
   Let the interest rate be r%
   We know that,
   S.I = PTR/100
   => (1540 x 5 x r)/100 + (1800 x 4 x r)/100 = 1788
   => r = 178800/14900 = 12%
5. If a sum of Rs.8000 lended for 20% per annum at compound interest then the sum of the amount will be Rs.13824 in
   A) 2 years
   B) 1year
   C) 3years
   D) 4years
   E) None
   
   View Answer

   Option C
   Solution:
   P = Rs.8000, R = 20% per annum
   P(1 + R/100)ⁿ
   Rs.13824 = 8000 * (1 + 20/100)ⁿ
   (12/10)³ = (12/10)ⁿ
   n=3
6. What will be the amount if sum of Rs.10,00,000 is invested at compound interest for 3 years with rate of interest 11%, 12% and 13% respectively?
   A) Rs.14,04,816
   B) Rs.12,14,816
   C) Rs.11,35,816
   D) Rs.16,00,816
   E) None
   
   View Answer

   Option A
   Solution:
   Here P=10,00,000 R1=11 R2=12 R3=13
   Amount after 3 yrs =p(1+R1/100)(1+R2/100)(1+R3/100)
   10,00,000*(1+11/100)(1+12/100)(1+13/100)=14,04,816.
7. Two persons P and Q borrowed Rs.40,000/- and Rs.60,000/- respectively from R at different rates of simple interest. The interest payable by P at the end of the first four years and that payable by Q at the end of the first three years is the same. If the total interest payable by P and Q for one year is Rs.8,400/- then at what rate did Q borrow the money from R?
   A) 8
   B) 10
   C) 12
   D) 9
   E) None
   
   View Answer

   Option B
   Solution:
   40000*4*R1/100=60000*3*R2/100
   R1=9/8R2
   1yr interest 40000*1*r1/100+60000*1*R2/100=8400
   4R2+6R2=84
   Then substitute 4(9/8R2)+6R2=84==> R2=8
8. In what time will Rs 390625 amount to Rs 456976 at 4% compound interest?
   A) 4
   B) 5
   C) 8
   D) 6
   E) None
   
   View Answer

   Option A
   Solution:
   P(1+r/100)^t = A
   390625(1+4/100)^t = 456976
   (1+1/25)^t = 456956 / 390625
   (26/25)^t = (26/25)⁴
   T = 4
   
9. The difference between C.I. and S.I. on a certain sum of money at 10% per annum for 3 years is Rs. 620. Find the principal if it is known that the interest is compounded annually.
   A) Rs. 2,00,000
   B) Rs. 20,000
   C) Rs. 10,000
   D) Rs. 1,00,000
   E) None
   
   View Answer

   Option B
   Solution:
   diff between CI and SI =P * r²/100³ * (300+r)
   620=p*100/100³ * 310
   P=Rs20,000
10. Shanthi borrowed Rs.75,000.00 from two banks at compound interest compound annually. One bank charges interest at the rate of 15% per year and the other bank at 20% per year. If at the end of the year, shanthi paid Rs.12,000.00 as the total interest to the two banks, how much did she borrow from the second bank?
    A) 18000
    B) 20000
    C) 15000
    D) 19000
    E) None
    
    View Answer

    Option C
    Solution:
    P*(1+r/100)=A
    75000*(100+r)/100=(75000+12000)87000
    100+r=116==>r=16%
    15…………….20
    …………16
    Ratio 4:1
    Total 5 == 75000
    1 ? == Rs15000.

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