BANK & INSURANCE (SIMPLE AND COMPOUND INTEREST) PART 3

Total Questions: 60

51. Find the difference between the interest of B and E, if they invested for 2 years and 3 years respectively? (Approximately)

Correct Answer: (a) 4391  
Solution:

Interest received by B = 30000 × [1 + 6/100]² − 30000 = 3708

Interest received by B = 20000 × [1 + 12/100]³ − 20000 = 8099

So, the required difference = 8099 − 3708 = 4391

52. Ragu invested Rs.72000 in two different parts one at 20% SI and another one at 20% CI (Compounded annually). What is the difference between the amount invested in SI and CI, if he received total interest at the end of two years is Rs.30480?

Correct Answer: (c) 12000
Solution:

Let us take one part x and another part 72000 − x

Total interest = x × 40/100 + (72000 − x) × 44/100 = 30480

10x + 7200 × 4 − 11x = 30480 × 25 = 30000

Required difference = 42000 − 30000 = 12000

53. Suresh invested Rs.80000 in two different parts one at the rate of 20% CI per annum and another one at the rate of 15% SI per annum. If he interchanges the rate of interest he got Rs.2875 less at the end of two years, and then find the difference of the two sums

Correct Answer: (a) Rs.20000  
Solution:

Let us take one part as x and another part as 80000 − x

Given,
(44/100 × x + (80000 − x) × 30/100) − (x × 32.25/100 + (80000 − x) × 40/100) = 2875

14x + 7.75x − 940000
= 287500

21.75x = 652500

x = 30000

Required difference = (80000 − 30000) − 30000 = 20000

54. Kamal invested Rs.2400 and Rs.3000, one at the rate of 10% SI per annum and another at x% SI per annum respectively. If he interchanges the rate of interest he got Rs.120 more at the end of two years, then find the value of x

Correct Answer: (c) 20%
Solution:(3000 × 2x/100 + 2400 × 20/100) − (3000 × 20/100 + 2400 × 2x/100) = 120
(60x + 480) − (600 + 48x) = 120
12x = 240
=> x = 20%

55. Priya invested Rs. x in SI at the rate of 20% per annum for two years and the same amount is invested in CI at the same rate of interest if she received Rs.860 more in interest as compared to S.I, then find the value of x.

Correct Answer: (a) Rs.21500  
Solution:Given,
x × 20/100 × 2 + 860 = x[(1 + 20/100)² − 1]
44/100 × x + 40/100 × x = 860
4x/100 = 860
=> x = 21500

56. Mukesh invested Rs.30000 in two different parts one at 15% SI and another one at 20% CI. At the end of two years he received total interest Rs.10750 then find the amount invested in SI?

Correct Answer: (d) Rs.17500  
Solution:

Given, (30000 − x) × 30/100 + x × 44/100 = 10750
9000 − 30x + 44x = 1075000
14x = 175000
=> x = 12500

Required sum = 30000 − 12500 = 17500

57. Akhilan invested some amount in SI at the rate of x% per annum for 2 years and Mathi also invested some amount at the rate of 20% CI per annum for 3 years and he received total interest Rs.2275. Find the value of x if Mathi invested Rs.625 less than Akhilan and interest received is Rs.25 more than Akhilan

Correct Answer: (e) 30%
Solution:

Let us take Mathi’s sum be y

2275 = (Y[(1 + 20/100)³ − 1])

2275 × 125/91 = Y
=> Y = 3125

Akhilan’s investment and interest are 3750 and 2250

3750 × x × 2/100 = 2250
=> x = 30%

58. A person invested sum of the amount at the rate of 15% SI per annum for two years and received total amount of Rs.19500. He invested same sum at the rate x% per annum compounded annually for two years and he received interest Rs.2100 more as compared to the Simple Interest, then find the value of ‘x’

Correct Answer: (d) 20%  
Solution:

Let us take sum be y

Given, 130/100 × y = 19500
=> y = 15000

S.I = 15000 × (15/100) × 2 = 4500

C.I = 4500 + 2100 = 6600

Total amount = 15000 + 6600 = 21600

15000(1 + x/100)² = 21600

(1 + x/100)² = (6/5)²

1 + x/100 = 6/5

=> x = 20%

59. The difference between the compound and simple interest on a certain sum at 12% per annum for two years is Rs. 90. What will be the value of the amount at the end of 3 years if compounded annually?

Correct Answer: (e) 8780.80
Solution:

Difference = P(R)²/100²

90 = P(12)²/(100)²

90 × 100²/12² = P

P = Rs. 6250

Now, calculating the compound interest on Rs. 6250 will be,

A = 6250(1 + 12/100)³

A = 6250(112/100)³

=> 6250(1.12)³

=> Rs. 8780.80

So, the compounded amount after three years will be Rs. 8780.80

60. The difference between compound interest and simple interest on a sum for two years at 8% per annum, where the interest is compounded annually is Rs.16, if the interest were compounded half yearly, the difference in two interests would be nearly?

Correct Answer: (a) Rs.24.64  
Solution:

For 1st year S.I = C.I

Thus, Rs.16 is the S.I. on S.I. for 1 year, which at 8% is thus Rs.200

i.e. S.I on the principal for 1 year is Rs.200

Principle = Rs.100 × 2008 × 1 = Rs.2500

Amount for 2 years, compounded half-yearly
Rs.2500 × 1.41404 = Rs.2924.4

C.I = Rs.424.64

Also, S.I = Rs.2500 × 8 × 2/100 = Rs.400

Hence, [(C.I) − (S.I)] = Rs. (424.64 − 400)
= Rs.24.64