Sail E0 Webinar

Quantitative Aptitude > Interest

SIMPLE INTEREST MCQs

Total Questions : 234 | Page 8 of 24 pages
Question 71. A sum of money was lent at simple interest at a certain rate for 3 years. Had it been lent at 2.5% per annum higher rate, it would have fetched Rs.540 more. The money lent was :
  1.    Rs.6472
  2.    Rs.6400
  3.    Rs.7200
  4.    Rs.6840
 Discuss Question
Answer: Option C. -> Rs.7200
Answer: (c)If the sum lent be Rs. x, then${x × 2.5 × 3}/100 = 540$$x = {540 × 100}/{2.5 × 3}$ = Rs.7200Using Rule 13,$P_1 = P, R_1 = R, T_1$ = 3$P_2 = P, R_2 = R + 2.5%, T_2$ = 3S.I. = Rs.540540 = ${P × (R + 2.5%) × 3 - P × R × 3}/100$54000 = 7.5PP = $540000/75$P = Rs.7200
Question 72. The simple interest on a sum of money is $8/25$ of the sum. If the number of years is numerically half the rate percent per annum, then the rate percent per annum is
  1.    8
  2.    5
  3.    4
  4.    6$1/4$
 Discuss Question
Answer: Option A. -> 8
Answer: (a)Using Rule 1Simple Interest (S.I.)= ${\text"Principal × Rate × Time"/100$ orS.I. = ${\text"P × R × T"/100$P = ${\text"S.I." × 100}/\text"R × T"$, R = ${\text"S.I." × 100}/\text"P × T"$, T = ${\text"S.I." × 100}/\text"P × R"$ A = P + S.I. or S.I. = A - P
Question 73. A certain sum doubles in 7 years at simple interest. The same sum under the same interest rate will become 4 times in how many years.
  1.    28
  2.    14
  3.    10
  4.    21
 Discuss Question
Answer: Option D. -> 21
Answer: (d)Case I,Interest = PrincipalRate = ${Interest × 100}/\text"Principal × Time"$= $100/7%$ per annumCase II,Interest = 3 × PrincipalTime = ${Interest × 100}/\text"Principal × Time"$= ${3 × 100}/{100/7}$ = 3 × 7 = 21 years
Question 74. At what per cent of simple interest will a sum of money double itself in 15 years?
  1.    6$2/3$%
  2.    6$1/3$%
  3.    6%
  4.    6$1/2$%
 Discuss Question
Answer: Option A. -> 6$2/3$%
Answer: (a)Let principal be Rs.x.Amount = Rs.2xInterest = Rs.(2x - x) = Rs.xRate = ${S.I. × 100}/\text"Principal × Time"$= ${x × 100}/{x × 15} = 20/3$= 6$2/3%$ per annum
Question 75. The rate of simple interest for which a sum of money becomes 5 times of itself in 8 years is :
  1.    40%
  2.    30%
  3.    55%
  4.    50%
 Discuss Question
Answer: Option D. -> 50%
Answer: (d)Principal = Rs.x (let)Amount = Rs.5xInterest = Rs.(5x - x) = Rs.4xRate = ${S.I. × 100}/\text"Principal × Time"$= ${4x × 100}/{x × 8}$ = 50% per annum
Question 76. A sum of money at a certain rate per annum of simple interest doubles in the 5 years and at a different rate becomes three times in 12 years. The lower rate of interest per annum is
  1.    20%
  2.    15%
  3.    16$2/3$%
  4.    15$3/4$%
 Discuss Question
Answer: Option C. -> 16$2/3$%
Answer: (c)The sum gets doubled in 5 years and tripled in 12 years.Clearly rate of interest for 12 years will be lower.Let Principal be x.then, Rate = ${SI × 100}/\text"Principal × Time"$= ${2x × 100}/{x × 12} = 50/3 = 16{2}/3%$Using Rule 3,$R_1 = {(2 - 1)}/5 × 100%$ = 20%$R_2 = {(3 - 1)}/12 × 100% = 16{2}/3%$Lower rate of interest =16$2/3%$
Question 77. A lent Rs.5000 to B for 2 years and Rs.3000 to C for 4 years on simple interest at the same rate of interest and received Rs.2200 in all from both as interest. The rate of interest per annum is
  1.    5%
  2.    7%
  3.    10%
  4.    7$1/8$%
 Discuss Question
Answer: Option C. -> 10%
Answer: (c)Using Rule 1,Let the rate of interest per annum be r%According to the question,${5000 × 2 × r}/100 + {3000 × 4 × r}/100 = 2200$100r + 120r = 2200220 r = 2200r = $2200/220$ = 10%
Question 78. A man had Rs.16,000, part of which he lent at 4% and the rest at 5% per annum simple interest. If the total interest received was Rs.700 in one year, the money lent at 4% per annum was
  1.    Rs.8,000
  2.    Rs.12,000
  3.    Rs.6,000
  4.    Rs.10,000
 Discuss Question
Answer: Option D. -> Rs.10,000
Answer: (d)Using Rule 1,Let the sum lent at 4% = Rs.xAmount at 5%= (16000 - x )According to the question,${x × 4 × 1}/100 + {(16000 - X) × 5 × 1}/100$ = 7004x + 80000 - 5x = 70000x = 80000 - 70000 = Rs.10000
Question 79. A certain sum of money amounts to Rs.756 in 2 years and to Rs.873 in 3$1/2$ years at a certain rate of simple interest. The rate of interest per annum is
  1.    11%
  2.    10%
  3.    13%
  4.    12%
 Discuss Question
Answer: Option C. -> 13%
Answer: (c)S.I. for 1$1/2$ years= Rs.(873 - 756) = Rs.117S.I. for 2 years= Rs.$(117 × 2/3 × 2)$ = Rs.156Principal = 756 - 156 = Rs.600Now, P = 600, T = 2, S.I. = 156R = ${100 × S.I.}/{P × T}$= ${100 × 156}/{600 × 2}$ = 13%Using Rule 12,Rate of interest= $({A_1 - A_2}/{A_2T_1 - A_1T_2})$ × 100= $({756 - 873}/{873 × 2 - 756 × 7/2}) × 100$= $({- 117}/{1746 - 2646}) × 100$= $({- 117}/{- 900})$ × 100 = 13%
Question 80. Rs.500 was invested at 12% per annum simple interest and a certain sum of money invested at 10% per annum simple interest. If the sum of the interest on both the sum after 4 years is Rs.480, the latter sum of money is :
  1.    Rs.750
  2.    Rs.450
  3.    Rs.550
  4.    Rs.600
 Discuss Question
Answer: Option D. -> Rs.600
Answer: (d)Using Rule 1,Simple interest gained from Rs.500= ${500 × 12 × 4}/100$ = Rs.240Let the other Principal be x.S.I. gained = Rs.(480 - 240) = Rs.240${x × 10 × 4}/100$ = 240$x = {240 × 100}/40$ = Rs.600

Latest Videos

Latest Test Papers