Directions: Read the followin questions carefully and answer them:
1
Find compound interest on Rs. 7000 at 21% per annum for 2 years 4 months, compounded annually.
A. Rs. 3824.9
B. Rs. 3966.1
C. Rs. 4094.4
D. Rs. 11109
2
Find the compound interest on Rs. 7500 in 2 years at 6% per annum, the interest being compounded half-yearly.
A. Rs. 941.31
B. Rs. 834.44
C. Rs.746.21
D. Rs. 764
3 Find the compound interest on Rs. 10,000 at 20% per annum for 6 months. compounded quarterly.
A. Rs.4353
B. Rs. 1329
C. Rs. 1025
D. Rs. 2649
4
If the simple interest on a sum of money at 5% per annum for 2 years is Rs. 1400, find the compound interest on the same sum for the same period at the same rate.
A. Rs. 1023
B. Rs. 1435
C. Rs. 3232
D. Rs. 1255
5
If Rs. 1000 amounts to Rs. 1166.40 in two years compounded annually, Find the rate of interest per annum.
A. 2% p.a
B. 4% p.a
C. 6% p.a
D. 8% p.a
6
If the compound interest on certain sum at 16
2
% for 3 years is Rs. 1270. Find the simple interest on
3
the same sum at the same rate for the same period .
A. Rs. 1202
B. Rs. 1104
C. Rs. 1080
D. Rs. 1432
7
The difference between the compound interest and simple interest on certain sum at 10% per annum for 2 years is Rs. 175. Find the sum .
A. Rs. 17500
B. Rs. 17854
C. Rs. 17533
D. Rs. 17132
8
The difference between the compound interest and simple interest accrued on an amount of Rs. 18,000 in 2 years was Rs. 720. What was the Rate of interest p.c.p.a.?
A. 5%
B. 10%
C. 15%
D. 20%
9
Divide Rs. 841 between A and B, so that the amount of A after 7 years is equal to the amount of B after 9 years, the interest being compounded at 5% per annum.
A. Rs. 441 and Rs. 400
B. Rs. 453 and Rs. 564
C. Rs. 321 and Rs. 583
D. Rs. 349 and Rs. 867
10
A certain sum amounts to Rs. 6250 in 2 years and to Rs. 6875 in 3 years. Find the sum.
A. Rs. 5674.69
B. Rs. 4233
C. Rs. 5254.45
D. Rs. 5165.29
Question No. 1
Correct Option: B
Explanation:
Time = 2 years 4 months = 2 | 4 | years = 2 | 1 | years. |
12 | 3 |
Let principal = P, Rate = R% per annum, Time = n years.
When interest is compounded annually. then,
Amount = P | [ | 1 + | R | ] | n |
100 |
So, amount = Rs | [ | 7000 × | [ | 1 + | 21 | ] | 2 | ] | × | [ | 1 + | 1/3 × 21 | ]] |
100 | 100 |
⇒ Rs. | [ | 7000 × | 121 | × | 121 | × | 107 | ] |
100 | 100 | 100 |
⇒ 10966.1.
So, C.I. = Rs. [10966.1 – 7000] ⇒ Rs. 3966.1.
Hence, option B is correct.
Question No. 2
Correct Option: A
Explanation:
When interest is compounded Half-yearly. then,
Amount = P | [ | 1 + | [R/2] | ] | 2T |
100 |
Principal = Rs. 7500; Rate = 3% per half - year; Time = 2 years = 4 half - years.
So, Amount = Rs. | [ | 7500 × | [ | 1 + | 3 | ] | 4 | ] |
100 |
⇒ Rs. | [ | 7500 × | 103 | × | 103 | × | 103 | × | 103 | ] |
100 | 100 | 100 | 100 |
⇒ Rs. 8441.31
⇒ C.I = Rs. [8441.31 - 7500] = Rs. 941.31.
Hence, option A is correct.
Question No. 3
Correct Option: C
Explanation:
P = 10000, T = 6 months, R = 20/4 = 5% [rate of interest apply quaterly]
By the net% effect we would calculate the effective compound rate of interest for 6 months = 10.25% [Refer to sub-details]
CI = 10.25% of 10000
CI = | 10.25 × 10000 | = 1025. |
100 |
_________________________________________________________________
Sub-details:
Calculation of effective compound rate of interest for 2 quaters [6 months] will be as follows.
Here, x = 5 and y = 5%
Net% effect = x + y = | xy | |
100 |
= 5 + 5 + | 5 × 5 | = 10 + 0.25 = 10.25% |
100 |
_______________________________________________________
Traditional Method:
When interest is compounded Quarterly. then,
Amount = P | [ | 1 + | [R/4] | ] | 4T |
100 |
Principal = Rs. 10000; Time = 6 months = 2 quarters; Rate = 20% per annum = 5% per quarter
So, Amount = Rs | [ | 10000 × | [ | 1 + | 5 | ] | 2 | ] |
100 |
⇒ Rs | [ | 10000 × | 21 | × | 21 | ] | ⇒ 11025. |
20 | 20 |
So, C.I = Rs [11025 – 10000] ⇒ Rs 1025.
Hence, option C is correct.
Question No. 4
Correct Option: B
Explanation:
We know, that
SI = rt% [rate of interest & time] and by the net% effect we would calculate the effective compound rate of interest for 2 years = 10.25% [Refer to sub-details]
1400 = [2 × 5]%
So, 10% ≡ ₹ 1400
10.25% ≡ ₹ x
By the cross multiplication, we get
x = | 1400 × 10.25 | = ₹ 1435. |
10 |
_______________________________________________________________________
Sub-details:
Calculation of effective compound rate of interest for 2 years will be as follows.
Here, x = 5 and y = 5%
Net% effect = x + y = | xy | |
100 |
= 5 + 5 + | 5 × 5 | = 10 + .25 = 10.25% |
100 |
_______________________________________________________________________
Traditional Method:
Clearly, Rate = 5% p.a, Time = 2 years, S.I = Rs. 1400.
So, principal = Rs. | [ | 100 × 1400 | ] | = Rs. 14000. |
2 × 5 |
Amount = Rs. | [ | 14000 × | [ | 1 + | 5 | ] | 2 | ] | ⇔ Rs. | [ | 14000 × | 21 | × | 21 | ] | ⇒ Rs. 15435. |
100 | 20 | 20 |
So, C.I = Rs. [15435 – 14000] = Rs. 1435.
Hence, option B is correct.
Question No. 5
Correct Option: D
Explanation:
Principal = Rs. 500; Amount = Rs. 583.20; Time = 2 years.
Let the rate be R% per annum. then,
[ | 1000 | [ | 1 + | R | ] | 2 | ] | = 1166.40. |
100 |
Or
[ | 1 + | R | ] | 2 | = | [ | 108 | ] | 2 |
100 | 100 |
⇒ 1 + | R | = | 108 | or R = 8. |
100 | 100 |
So, Rate = 8% p.a
Hence, option D is corret.
Question No. 6
Correct Option: C
Explanation:
Let the sum be Rs. x, then,
C.I = | [ | x × | [ | 1 + | 50 | ] | 3 | – x | ] | = | [ | 343x | – x | ] | = | 127x | . |
3 × 100 | 216 | 216 |
So, | 127x | = 1270 or x = | 1270 × 216 | = 2160. |
216 | 127 |
Thus, the sum is Rs. 2160.
So, S.I = Rs | [ | 2160 × | 50 | × 3 × | 1 | ] | = Rs 1080. |
3 | 100 |
Hence, option C is correct.
Question No. 7
Correct Option: A
Explanation:
Method I:
To solve this question, we can apply a short trick approach
Sum = | Difference × 1002 |
r2 |
Given,
Difference = 175, r = 10%
By the short trick approach, we get
Sum = | 175 × 1002 | = 17500/- |
102 |
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Method II:
We can solve it by the net% formula,
Rate % of SI for 2 yr at 10% pa = 10 × 2 = 20%
Rate % of CI for 2 yr at 10% pa,
= 10 + 10 + | 10 × 10 | = 21% | |
100 |
% rate difference of CI and SI = 21% – 20 = 1%
Let the sum be x, then
1% of x = 175
x = | 175 × 100 | = ₹ 17500 |
1 |
Hence, option A is correct.
Question No. 8
Correct Option: D
Explanation:
To solve this question, we can apply a short trick approach
Sum = | Difference × 1002 |
r2 |
Given,
Sum [Amount] = 18000, Difference = 720, r = ?
By the short trick approach, we get
18000 = | 720 × 1002 | ⇒ r2 = | 720 × 1002 | ⇒ r2 = 400 ⇒ r = 20% |
r2 | 18000 |
Hence, option D is correct.
Question No. 9
Correct Option: A
Explanation:
Let the two parts be Rs. x and Rs. [841 – x].
x | [ | 1 + | 5 | ] | 7 | = [841 – x] | [ | 1 + | 5 | ] | 9 |
100 | 100 |
⇒ | x | = | [ | 1 + | 5 | ] | 2 | = | [ | 21 | × | 21 | ] | . |
[841 – x] | 100 | 20 | 20 |
⇒ 400x = 441 [841 – x] ⇒ 841x = 441 × 841 ⇒ x = 441.
So, the two parts are Rs. 441 and Rs. [841 – 441] i.e Rs. 441 and Rs. 400.
Hence, option A is correct.
Question No. 10
Correct Option: D
Explanation:
SI for 1 year = Rs.[6875 – 6250] = Rs. 625.
So, Rate = | [ | 100 x 625 | ] | % = 10%. |
6250 × 1 |
Let the sum be Rs. x, then,
x | [ | 1 + | 10 | ] | 2 | = 6250 ⇔ x × | 11 | × | 11 | = 6250. |
100 | 10 | 10 |
⇒ x = | [ | 6250 × | 100 | ] | = 5165.29. |
121 |
So, Sum = Rs. 5165.29.
Hence, option D is correct.