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 76 of 118 pages

Question 751. A sum of money amounts to Rs.850 in 3 years and to Rs.925 in 4 years at some rate of simple interest. The sum is :

Rs.600
Rs.550
Rs.700
Rs.625

Discuss Question

Answer: Option D. -> Rs.625
Answer: (d)Interest for 1 year= Rs.(925 - 850) = Rs.75If a sum becomes $a_1$ in $t_1$ years and $a_2$ in $t_2$ years then rate of interest= ${100(a_2 - a_1)}/({a_1t_2 - a_2t_1})%$= ${100(925 - 850)}/{850 × 4 - 3 × 925} = 7500/625$ = 12%Principal = ${SI × 100}/{\text"Time × Rate"$= ${75 × 100}/{1 × 12}$ = Rs.625Using Rule 12,P = $({A_2T_1 - A_1T_2}/{T_1 - T_2})$= ${925 × 3 - 850 × 4}/{3 - 4}$= ${2775 - 3400}/{-1}$= ${- 625}/{- 1}$ = Rs.625

Question 752. What sum will amount to Rs.7000 in 5 years at 3$1/3$% simple interest ?

Rs.6500
Rs.6300
Rs.5000
Rs.6000

Discuss Question

Answer: Option D. -> Rs.6000
Answer: (d)Using Rule 1,P = ${A × 100}/{100 + r × t}$=${7000 × 100}/{100 + 10/3 × 5}$= ${7000 × 100 × 3}/350$ = Rs.6000

Question 753. If the simple interest on a certain sum of money for 15 months at 7$1/2$% per annum exceeds the simple interest on the same sum for 8 months at 12$1/2$% per annum by Rs.32.50, then the sum of money (in ) is :

312.50
312
3120.50
3120

Discuss Question

Answer: Option D. -> 3120
Answer: (d)Using Rule 1,Let the sum be x.Using formula, I = $\text"PRT"/100$ we have${x × 15/12 × 15/2}/{100 - x} - {x × 8/12 × 25/2}/100$= 32.50${25x}/2400$ = 32.50$x = {32.50 × 2400}/25$ = 3120Required sum = Rs.3120

Question 754. What sum of money will amount to Rs.520 in 5 years and to Rs.568 in 7 years at simple interest ?

Rs.120
Rs.400
Rs.220
Rs.510

Discuss Question

Answer: Option B. -> Rs.400
Answer: (b)Simple interest for 2 years= Rs.(568 - 520) = Rs.48Interest for 5 years= Rs.$48/2 × 5$ = Rs.120Principal = Rs.(520 - 120) = Rs.400Using Rule 12,P = $({A_2T_1 - A_1T_2}/{T_1 - T_2})$=$({568 × 5 - 520 × 7}/{5 - 7})$= $({2840 - 3640}/{-2})$=${- 800}/{- 2}$ = Rs.400

Question 755. A person deposited Rs.400 for 2 years, Rs.550 for 4 years and Rs.1,200 for 6 years. He received the total simple interest of Rs.1,020. The rate of interest per annum is

Discuss Question

Answer: Option B. -> 10%
Answer: (b)Using Rule 1,Let the rate of interest be R per cent per annum.${400 × 2 × R}/100 + {550 × 4 × R}/100$+ ${1200 × 6 × R}/100 = 1020$8R + 22 R +72 R = 1020102 R= 1020R = $1020/102$ = 10%

Question 756. Manoj deposited Rs.29400 for 6 years at a simple interest. He got Rs.4200 as interest after 6 years. The annual rate of interest was

2$7/20$%
2$8/21$%
4$8/21$%
3$8/21$%

Discuss Question

Answer: Option B. -> 2$8/21$%
Answer: (b)Using Rule 1,4200 = ${29400 × 6 × R}/100$R = $4200/{294 × 6} = 50/21 = 2{8}/21$%

Question 757. The simple interest on Rs.7,300 from 11 May, 1987 to 10 September, 1987 (both days included) at 5% per annum is

Rs.103
Rs.123
Rs.223
Rs.200

Discuss Question

Answer: Option B. -> Rs.123
Answer: (b)Using Rule 1,Time from 11 May to 10 September, 1987= 21 + 30 + 31 + 31 + 10= 123 daysTime = 123 days = $123/365$ yearS.I. = ${7300 × 123 × 5}/{365 × 100}$ = Rs.123

Question 758. At some rate of simple interest, A lent Rs.6,000 to B for 2 years and Rs.1,500 to C for 4 years and received Rs.9,00 as interest from both of them together. The rate of interest per annum was

Discuss Question

Answer: Option B. -> 5%
Answer: (b)Using Rule 1,If rate of interest be R% p.a. then,SI = ${\text"Principal × Rate × Time"/100$${6000 × 2 × R}/100 + {1500 × 4 × R}/100$= 900120 R + 60R = 900180R = 900R = $900/180$ = 5%

Question 759. What annual instalment will discharge a debt of Rs.6450 due in 4 years at 5% simple interest ?

Rs.1835
Rs.1500
Rs.1950
Rs.1935

Discuss Question

Answer: Option B. -> Rs.1500
Answer: (b)Let each instalment be x Then,$(x + {x × 5 × 1}/100) + (x + {x × 5 × 2}/100)$+ $(x + {x × 5 × 3}/100) + x = 6450$$(x + x/20) + (x + x/10)$+ $(x + {3x}/20)$ + x= 6450${21x}/20 + {11x}/10 + {23x}/20 + x = 6450$${21x + 22x + 23x + 20x}/20$= 6450${86x}/20 = 6450$$x = {6450 × 20}/86$ = Rs.1500 Using Rule 10If a sum is to be deposited in equal instalments, then,Equal instalment = ${A × 200}/{T[200 + (T - 1)r]}$where T = no. of years, A = amount, r = Rate of Interest.

Question 760. Rs.1,000 is invested at 5% per annum simple interest. If the interest is added to the principal after every 10 years, the amount will become Rs.2,000 after

18 years
15 years
16$2/3$ years
20 years

Discuss Question

Answer: Option C. -> 16$2/3$ years
Answer: (c)Using Rule 1,After 10 years,SI = ${1000 × 5 × 10}/100$ = Rs.500Principal for 11th year= 1000 + 500 = Rs.1500SI = Rs.(2000 - 1500) = Rs.500T = ${SI × 100}/{P × R} = {500 × 100}/{1500 × 5}$= $20/3$ years = 6$2/3$ yearsTotal time = 10 + 6$2/3$= 16$2/3$ years