Simple & Compound Interest(Quantitative Aptitude > Interest ) Questions and answers for exam Preparation

Quantitative Aptitude > Interest

SIMPLE & COMPOUND INTEREST MCQs

Compound Interest, Simple Interest, Interest (combined)

Total Questions : 1171 | Page 86 of 118 pages

Question 851. 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

Rs.8,000
Rs.12,000
Rs.6,000
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 852. If the annual rate of simple interest increases from 10% to 12$1/2$% , a man's yearly income increases by Rs.1250. His principal (in rupees) is

45,000
50,000
65,000
60,000

Discuss Question

Answer: Option B. -> 50,000
Answer: (b)Using Rule 1,Change in SI= $(25/2 - 10)% = 5/2%$$5/2$% of principal = Rs.1250Principal = Rs.${1250 × 2 × 100}/5$ = Rs.50000

Question 853. A person who pays income tax at the rate of 4 paise per rupee, find that a fall of interest rate from 4% to 3.75% diminishes his net yearly income by Rs.48. What is his capital ?

Rs.25,000
Rs.24,000
Rs.18,000
Rs.20,000

Discuss Question

Answer: Option D. -> Rs.20,000
Answer: (d)If the capital after tax deduction be x, thenx × (4 - 3.75) % = 48${x × 0.25}/100$ = 48${x × 25}/10000$ = 48$x/400$ = 48x = 48 × 400 = Rs.19200Required capital= ${19200 × 100}/96$ = Rs.20000

Question 854. A sum was invested on simple interest at a certain rate for 2 years. Had it been put at 3% higher rate, it would have fetched Rs.72 more. The sum is

Rs.1,500
Rs.1,200
Rs.1,800
Rs.1,600

Discuss Question

Answer: Option B. -> Rs.1,200
Answer: (b)Let the sum = P and original rate = R% per annum.Then, ${P × (R + 3) × 2}/100 - {P × R × 2}/100 = 72$${P × 3 × 2}/100 = 72$P = ${72 × 100}/{3 × 2}$ = Rs.1200 Using Rule 13The difference between the S.I. for a certain sum $P_1$ deposited for time $T_1$ at $R_1$ rate of interest and another sum $P_2$ deposited for time $T_2$ at $R_2$ rate of interest isS.I. = ${P_2R_2T_2 - P_1R_1T_1}/100$

Question 855. A sum of Rs. 800 amounts to Rs.920 in 3 years at the simple interest rate. If the rate is increased by 3% p.a., what will be the sum amount to in the same period ?

Rs.962
Rs.992
Rs.982
Rs.942

Discuss Question

Answer: Option B. -> Rs.992
Answer: (b)Using Rule 1,Case I,S.I. = 920 - 800 = Rs.120Rate = ${\text"S.I." × 100}/\text" Principal × Time"$= ${120 × 100}/{800 × 3}$ = 5% per annumCase II,Rate = 8% per annumS.I. = ${800 × 8 × 3}/100$ = Rs.192Amount = Principal + S.I.= (800 + 192) = Rs.992

Question 856. A certain sum of money becomes three times of itself in 20 years at simple interest. In how many years does it become double of itself at the same rate of simple interest ?

10 years
8 years
14 years
12 years

Discuss Question

Answer: Option A. -> 10 years
Answer: (a)Case-ILet the principal be xAmount = 3xInterest = 2xTime = 20 yearsI = $\text"PRT"/100$2x = ${x × R × 20}/100$ ⇒ R = 10%Case-III = x, P = x, R = 10, T = ?I = $\text"PRT"/100$x = ${x × 10 × T}/100$ ⇒ T = 10 years.Using Rule 3,R% = ${(3 - 1)}/20$ × 100% = 10%Now, T = ${(n - 1)}/R$ yearsT = ${2 - 1}/10 × 100$ = 10 years

Question 857. In how much time, will a sum of money become double of itself at 15% per annum simple interest?

6$1/2$ years
6$1/4$ years
6$2/3$ years
6$1/3$ years

Discuss Question

Answer: Option C. -> 6$2/3$ years
Answer: (c)If the principal be x, the amount = 2xSI = xTime = ${SI × 100}/\text"Principal × Rate"$= ${x × 100}/{x × 15} = 20/3 = 6{2}/3$ yearsUsing Rule 3,T = ${(n - 1)}/R × 100%$= $({2 - 1}/15) × 100$= $100/15 = 20/3$ Years= 6$2/3$ years

Question 858. At what rate per cent per annum will the simple interest on a sum of money be $2/5$ of the amount in 10 years ?

6%
4%
6$2/3$%
5$2/3$%

Discuss Question

Answer: Option C. -> 6$2/3$%
Answer: (c)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 859. If a sum of money deposited in a bank at simple interest is doubled in 6 years, then after 12 years, the amount will be

3 times the original amount
$5/2$ times the original amount
4 times the original amount
$7/2$ times the original amount

Discuss Question

Answer: Option A. -> 3 times the original amount
Answer: (a)Case I,Principal = Rs.xInterest = Rs.xTime = 6 yearsRate = ${Interest × 100}/\text"Principal × Time"$= ${x × 100}/{x × 16} = 50/3%$ per annumCase II,Interest = ${x × 12 × 50}/{100 × 3}$ = Rs.2xi.e., Amount is thrice the principal.

Question 860. In how many years will a sum of money double itself at 12% per annum?

6 yrs. 9 months
8 yrs. 6 months
7 yrs. 6 months
8 yrs. 4 months

Discuss Question

Answer: Option D. -> 8 yrs. 4 months
Answer: (d)If the principal be Rs.100 then S.I. = Rs.100.Time = ${SI × 100}/\text"Principal × Rate"$= ${100 × 100}/{100 × 12} = 25/3$ years= 8 years 4 monthsUsing Rule 3,T = ${(n - 1)}/R × 100%$= ${(2 - 1)}/12 × 100%$= $100/12 = 25/3$ years.= 8$1/3$ years= 8 years, 4 months.