Quantitative Aptitude: Simple/Compound Interest Set 23

  1. A sum of rs.P invested on compound interest annually at certain rate of interest and it three times itself in five years. In how many years the amount to 9 times itself at the same rate of interest ?
    5 years
    8 years
    7 years
    10 years
    12 years
    Option D
    3P = P(1 + R/100)^5
    3 = (1 + R/100)^5
    3^2 = (1 + R/100)5*2
    9 = (1 + R/100)^10
    time = 10 years

     

  2. A lends rs. 5500 to B at 20% per annum and B lends the same sum to C at 22% per annum. Find the gain of B after 2 years in simple interest.
    380
    275
    220
    440
    554
    Option C
    B gives the interest to A after 2 years,
    5500 * 20/100 * 2 = 2200
    C gives the interest to B after 2 years
    5500 * 22/100 * 2 = 2420
    the gain of B = 2420 – 2200 = 220

     

  3. Difference between compound interest and simple interest on sum of rs.4800 at certain rate of interest after 2 years is rs. 108. What is the rate of interest ?
    14%
    15%
    17%
    12.5%
    24%
    Option B
    CI – SI = PR^2/100^2
    108 = 4800R^2/10000
    R^2 = 108 * 10000/4800
    P^2 = 225
    R = 15%

     

  4. After two years ratio between simple interest to principle is 2 : 5. If difference between CI and SI after two years is 208, then find principle ?
    4800
    4750
    4540
    4850
    5200
    Option E
    Let principle = 5x
    and SI = 2x
    rate of interest for two years = 2x/5x * 100 = 40%
    rate of interest for 1 years = 40%/2 = 20%
    CI – SI = PR^2/100^2
    208 = P (20)^2/10000
    P = 5200

     

  5. Two persons P and Q invested rs. (x + 3400) and (x+ 2200) at the rate of 15% and 20% respectively for two years in simple interest. After two years total SI is rs.7220, then how much amount invested by Q ?
    7600
    9820
    5840
    6450
    9240
    Option A
    (x + 3400) * 15 /100 * 2 + (x + 2200) * 20/100 * 2 =7220
    (x + 3400) * 3/10 + (x+2200)*2/5 = 7220
    (3x + 102000/10) + (2x + 4400/5) = 7220
    (3x + 10200 + 4x + 8800/10) = 7220
    7x + 19000 = 72200
    x = 7600

     

  6. Total sum of rs.4740 is invested by two friends A and B in a scheme at the rate interest of 12% p.a for 4 year in SI. If interest received by B is 67.20 more than interest received by A, then find how much amount invested by A ?
    2800
    2300
    1840
    2350
    none of these
    Option B
    A invested = x
    B invested = 4740 – x
    (4740 – x) 12/100 * 4 – x * 12/100 * 4 = 67.20
    48/100 ( 4740 – x – x) = 6720
    12/25 (4740 – 2x) = 67.20
    4740 – 2x = 67.20 * 25/12
    4740 – 2x = 140
    2x = 4600
    x = 2300
    amount invests by A= 2300

     

  7. What is the compound interest accrued on a sum of 1400 at the rate of 6% in 2 years ?
    184.25
    254.08
    334.05
    173.04
    234.14
    Option D
    Compound interest for 2 years
    6 + 6 + 6 * 6/100 = 12.36 %
    compound interest = 1400 * 12.36/100 = 173.04

     

  8. The compound interest on a certain sum at 20% p.a for 2 years is rs. 98 more than the simple interest on same sum at 15% per annum for 2 years. What is the sum ?
    700
    480
    320
    1000
    650
    Option A
    Let sum is rs.x
    compound interest for 2 years at 20 % p.a
    20 + 20 + 20 * 20 /100 = 44%
    simple interest for 2 years at 15 % = 15% * 2 = 30%
    x * 44/100 – x * 30/100 = 98
    x = 700

     

  9. A certain sum is deposited at rate of 40% p.a on Compound interest. Difference between interest earned at the 1st and 2nd year is rs.384. What is the sum ?
    4800
    4500
    3200
    4500
    2400
    Option E
    Let sum = 100x
    interest of 1st year = 100x * 40/100 = 40x
    total amount at the end of the 1st year = 100x + 40x = 140x
    interest of 2nd year = 140x * 40/100 = 56x
    difference = 56x – 40x = 16x
    16x = 384
    x = 24
    sum = 100x = 100 * 24 = 2400

     

  10. What is difference between the compound interest on rs.4000 for 1.5 years at 40% p.a compounded yearly and half-yearly ?
    182
    192
    534
    314
    208
    Option B
    Rate of interest after 1.5 years compounded yearly at 40%p.a
    40 + 20 + 800/100 = 68%
    CI = 4000 * 68/100 = 2720
    Rate of interest after 1.5 years compounded half-yearly
    rate of interest = 40/2 = 20%
    20 + 20 + 20 * 20 /100 = 44%
    44% + 20% + 880/100 = 72.80%
    CI = 4000 * 72.80 /100 = 2912
    difference = 2912 – 2720 = 192

     

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