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 67 of 118 pages

Question 661. There is 40% increase in an amount in 8 years at simple interest. What will be the compound interest (in rupees) of Rs 30000 after 2 years at the same rate ?

3075
6150
4612.5
7687.5

Discuss Question

Answer: Option A. -> 3075
Answer: (a)According to the question,If principal= Rs.100 then interest = Rs.40.Case I.Rate = $\text"S.I. × 100"/ \text"Principal × Time"$= ${40 × 100}/{100 × 8}$ = 5% per annumCase II.A = P$(1 + R/100)^T$= 30000$(1 + 5/100)^2$= 30000$(1 + 1/20)^2$= 30000$({20 + 1}/20)^2$= 30000$ × 21/20 × 21/20$= Rs.33075C. I. = Rs.(33075 - 30000) = Rs.3075

Question 662. The simple interest on a sum of money at 4% per annum for 2 years is Rs.80. The compound interest in the same sum for the same period is

Rs.81.60
Rs.82.60
Rs.81.80
Rs.82.20

Discuss Question

Answer: Option A. -> Rs.81.60
Answer: (a)Principal = $\text"S.I. × 100"/ \text"Time × Rate"$= ${80 × 100}/{2 × 4}$ = Rs.1000C.I. = P$[(1 + R/100)^T - 1]$= 1000$[(1 + 4/100)^2 - 1]$= 1000$[(25/26)^2 - 1]$= 1000$(676/625 - 1)$= 1000$({676 - 625}/625)$= ${1000 × 51}/625$= Rs.81.60Using Rule 10,Here, S.I. = Rs.80, R = 4%, C.I. = ?C.I.= S.I.$(1 + R/200)$C.I.= 80$(1 + 4/200)$= $80(1 + 1/50)$= 80 × $51/50$ = Rs.81.60

Question 663. On a certain sum of money the compound interest for 2 years is Rs.282.15 and the simple interest for the same period of time is Rs.270. The rate of interest per annum is

12.15%
6.07%
9%
10%

Discuss Question

Answer: Option C. -> 9%
Answer: (c)Using Rule 10,If SI on a certain sum for two years is x and CI is y, then$y = x(r + /200)$$282.15 = 270(1 + r/100)$$1 + r/200 = 282.15/270$$r/200 = 282.15/270$ - 1$r/200 = {12.15}/270$r = ${12.15 × 200}/270 = 9%$

Question 664. At a certain rate per annum, the simple interest on a sum of money for one year is Rs.260 and the compound interest on the same sum for two years is Rs.540.80. The rate of interest per annum is

Discuss Question

Answer: Option C. -> 8%
Answer: (c)Using Rule 1,If A = Amount, P = Principal, r = Rate of Compound Interest (C.I.), n = no. of years then,A=P$(1 + r/100)^n$, C.I. = A - PC.I. = P$[(1 + r/100)^n - 1]$

Question 665. If the compound interest on a sum for 2 years at 12$1/2$ p.a is Rs.510, the simple interest on the same sum at the same rate for the same period of time is

Rs.480
Rs.400
Rs.460
Rs.450

Discuss Question

Answer: Option A. -> Rs.480
Answer: (a)Principal = Rs.P (let)C.I. = P$[(1 + R/100)^T - 1]$510 = P$[(1 + 25/200)^2 - 1]$510 = P$[(1 + 1/8)^2 - 1]$510 = P$[(9/8)^2 - 1]$510 = P$(81/64 - 1)$510 = P$({81 - 64}/64)$510 = ${17P}/64$P = ${510 × 64}/17$ = Rs.1920S.I. = $\text"Principal × Time × Rate"/100$= ${1920 × 2 × 25}/{100 × 2}$ = Rs.480Using Rule 10,Here, C.I. = Rs.510, R = 12$1/2$%, S.I. = ?C.I. = S.I.$(1 + R/200)$510 = S.I.$(1 + 25/400)$510 = S.I.$(425/400)$S.I. = ${510 × 400}/425$ = Rs.480

Question 666. A sum becomes Rs.2,916 in 2 years at 8% per annum compound interest. The simple interest at 9% per annum for 3 years on the same amount will be

Rs.625
Rs.600
Rs.650
Rs.675

Discuss Question

Answer: Option D. -> Rs.675
Answer: (d)Using Rule 1,A = P$(1 + R/100)^T$2916 = $x(1 + 8/100)^2$2916 = $x(27/25)^2$$x = {2916 × 25 × 25}/{27 × 27}$ = Rs.2500S.I. = ${P × R × T}/100$= ${2500 × 9 × 3}/100$ = Rs.675

Question 667. If the compound interest on a sum for 2 years at 12$1/2$% per annum is Rs.510, the simple interest on the same sum at the same rate for the same period of time is :

Rs.460
Rs.400
Rs.450
Rs.480

Discuss Question

Answer: Option D. -> Rs.480
Answer: (d)C.I. = P$[(1 + R/100)^T - 1]$510 = P$[(1 + 25/200)^2 - 1]$510 = P$(81/64 - 1)$P = ${510 × 64}/17$ = 1920S.I. = ${1920 × 2 × 25}/{100 × 2}$ = Rs.480Using Rule 10,Here, C.I. = Rs.510, R = 12$1/2$%, S.I. = ?C.I. = S.I.$(1 + R/200)$$510 = S.I.(1 + 25/400)$S.I. = ${510 × 400}/425$ = Rs.480

Question 668. If the compound interest on a certain sum for 2 years at 4% p.a. is Rs.102, the simple interest at the same rate of interest for two years would be

Rs.100
Rs.200
Rs.150
Rs.50

Discuss Question

Answer: Option A. -> Rs.100
Answer: (a)If the sum be P, thenC.I. = P$[(1 + R/100)^T - 1]$102 = $[(1 + 4/100)^2 - 1]$102 = P$[(26/25)^2 - 1]$102 = P$(676/625 - 1)$102 = P$({676 - 625}/625)$102 = P × $51/625$P = ${102 × 625}/51$ = Rs.1250S.I. = ${1250 × 2 × 4}/100$ = Rs.100

Question 669. A bank offers 5% compound interest calculated on half-yearly basis. A customer deposits Rs. 1600 each on 1st January and 1st July of a year. At the end of the year, the amount he would have gained by way of interest is:

Rs. 120
Rs. 121
Rs. 122
Rs. 123

Discuss Question

Answer: Option B. -> Rs. 121
Answer: (b).Rs. 121

Question 670. There is 60% increase in an amount in 6 years at simple interest. What will be the compound interest of Rs. 12,000 after 3 years at the same rate?