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 79 of 118 pages

Question 781. Equal sum of money are lent to X and Y at 7.5% per annum for a period of 4 years and 5 years respectively. If the difference in interest, paid by them was Rs.150, the sum lent to each was

Rs.1000
Rs.500
Rs.3000
Rs.2000

Discuss Question

Answer: Option D. -> Rs.2000
Answer: (d)Let the sum lent be x.${x × 7.5 × 5}/100 - {x × 7.5 × 4}/100 = 150$${x × 7.5 × 1}/100$ = 150$x = {150 × 100}/{7.5}$ = Rs.2000Using Rule 13,Here, $P_1 = P, R_1 = 7.5%, T_1$ = 4 years.$P_2 = P, R_2 = 7.5%, T_2$ = 5 years.S.I. = Rs.150S.I. = ${P_2R_2T_2 - P_1R_1T_1}/100$150 = ${P × 7.5 × 5 - P × 7.5 × 4}/100$15000 = 7.5PP = $15000/{7.5}$P = $150000/75$ = Rs.2000

Question 782. A sum of Rs.1500 is lent out in two parts in such a way that the simple interest on one part at 10% per annum for 5 years is equal to that on another part at 12.5% per annum for 4 years. The sum lent out at 12.5% is :

Rs.1000
Rs.500
Rs.1250
Rs.750

Discuss Question

Answer: Option D. -> Rs.750
Answer: (d)Using Rule 1,Let the sum lent out at 12.5% be xSum lent out at 10% = 1500 - xNow, ${(1500 - x) × 10 × 5}/100$= ${x × 12.5 × 4}/100$50 (1500 - x ) = 50x2x = 1500$x = 1500/2$ = Rs.750

Question 783. If the simple interest for 6 years be equal to 30% of the principal, it will be equal to the principal after

30 years
20 years
22 years
10 years

Discuss Question

Answer: Option B. -> 20 years
Answer: (b)Let the principal be P and rate of interest be r %According to the question,${30P}/100 = {P × R × 6}/100$30 = 6 RR = 5Now, let interest be equal to principal in T years.P = ${P × 5 × T}/100$T = $100/5$ = 20 years.Using Rule 5,Here, n = $30/100 = 3/10$, T = 6 years.RT = n × 100R × 6 = $3/10$ × 100R = 5%As,S.I. = PS.I. = ${P × R × T}/100$100 = RT100 = 5 × TThis is possible only when T = 20.

Question 784. Mohan lent some amount of money at 9% simple interest and an equal amount of money at 10% simple interest each for two years. If his total interest was Rs. 760, what amount was lent in each case ?

Rs.1800
Rs.1700
Rs.2000
Rs.1900

Discuss Question

Answer: Option C. -> Rs.2000
Answer: (c)Using Rule 1,Let the sum lent in each case be x.Then, ${x × 9 × 2}/100 + {x × 10 × 2}/100$ = 760${x × 2}/100$(9 + 10) = 760${2 × 19x}/100$ = 760$x = {760 × 100}/{2 × 19}$ = Rs.2000

Question 785. Simple interest on Rs.500 for 4 years at 6.25% per annum is equal to the simple interest on Rs.400 at 5% per annum for a certain period of time. The period of time is

5 years
4 years
8$2/3$ years
6$1/4$ years

Discuss Question

Answer: Option D. -> 6$1/4$ years
Answer: (d)Using Rule 1,Let the period of time be T years. Then,${400 × 5 × T}/100 = {500 × 4 × 6.25}/100$T = ${500 × 4 × 6.25}/{400 × 5}$= $25/4 = 6{1}/4$ years

Question 786. The difference between the simple interest received from two different banks on Rs.500 for 2 years is Rs.2.50. The difference between their (per annum) rate of interest is :

0.25%
0.10%
1.00%
0.50%

Discuss Question

Answer: Option A. -> 0.25%
Answer: (a)${500 × 2 × R_1}/100 - {500 × 2 × R_2}/100$ = 2.5where $R_1 & R_2$ are rate% of both banks10 $(R_1 - R_2 )$ = 2.5$R_1 - R_2 = {2.5}/10$= 0.25 % per annum Using Rule 7If the difference between two simple interests is 'x' calculated at different annual rates and times, then principal (P) isP = $ {x × 100}/{(\text"difference in rate") ×(\text"difference in time")}$

Question 787. A sum was lent at simple interest at a certain rate for 2 years. Had it been lent at 3% higher rate, it would have fetched Rs.300 more. The original sum of money was :

Rs.6000
Rs.5000
Rs.4000
Rs.7000

Discuss Question

Answer: Option B. -> Rs.5000
Answer: (b)If the principal be x, then${x × 3 × 2}/100 = 300$$x = {300 × 100}/{3 × 2}$ = Rs.5000Using Rule 13.$P_1 = P, R_1 = R, T_1$ = 2.$P_2 = P, R_2 = R + 3, T_2$ = 2.S.I.= Rs.300300 = ${P × (R + 3) × 2 - PR2}/100$300 = ${6P}/100$ = Rs.5000

Question 788. The rate of simple interest per annum of bank being decreased from 5% to 3$1/2$%, the annual income of a person from interest was less by Rs. 105. The sum deposited at the bank was

Rs.7,200
Rs.6,000
Rs.7,000
Rs.6,800

Discuss Question

Answer: Option C. -> Rs.7,000
Answer: (c)Using Rule 1,Amount deposited in bank = Rs.x (let)Difference of rates= 5 - $7/2 = 3/2%$ per annumS.I. = ${\text"Principal × Time × Rate"/100$${x × 1 × 3}/{100 × 2}$ = 105$x = {105 × 200}/3$ = Rs.7000

Question 789. A sum of money was invested at a certain rate of simple interest for 2 years . Had it been invested at 1% higher rate, it would have fetched Rs.24 more interest. The sum of money is :

Rs.1050
Rs.1200
Rs.9600
Rs.1000

Discuss Question

Answer: Option B. -> Rs.1200
Answer: (b)${P × 1 × 2}/100 = 24$P = $2400/2$ = Rs.1200Using Rule 13,$P_1 = P, R_1 = R, T_1$ = 2.$P_2 = P, R_2 = R + 1, T_2$ = 2S.I.= Rs. 2424 = ${P(R +1)2 - PR2}/100$2400 = 2PR + 2P - 2PRP = Rs.1200

Question 790. A sum of Rs.400 amounts to Rs.480 in 4 years. What will it amount to if the rate of interest is increased by 2%?

Rs.560
Rs.484
None of these
Rs.512

Discuss Question

Answer: Option D. -> Rs.512
Answer: (d)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