A sum of Tk. 30,000 yields a compound interest of Tk. 4347 when invested at 7% per annum. What is the investment period in years?
A
2 years
B
4 years
C
3 years
D
5 years
উত্তরের বিবরণ
Question: A sum of Tk. 30,000 yields a compound interest of
Tk. 4347 when invested at 7% per annum. What is the investment period in years?
Solution:
Given,
Principal, P = 30000
Rate, r = 7% per annum
Compound Interest, CI = 4347
We know,
Amount, A = P + CI = 30000 + 4347 = 34347
Using the compound amount formula:
A = P(1 + r/100)n
⇒
34347 = 30000 × (1 + 7/100)n
⇒
34347 = 30000 × (107/100)n
⇒
(107/100)n = 34347/30000
⇒
(1.07)n = 1.1449
⇒
(1.07)n = (1.07)2
∴
n = 2 years
0
Updated: 1 month ago
Two numbers are in the ratio 2 : 3. If 4 is subtracted from the first number, the ratio becomes 1 : 2. What are the numbers?
Created: 1 month ago
A
14, 21
B
16, 24
C
18, 27
D
20, 30
Question: Two numbers are in the ratio 2 : 3. If 4 is
subtracted from the first number, the ratio becomes 1 : 2. What are the
numbers?
Solution:
Let the two numbers be: 2x and 3x
According to the question,
(2x - 4)/3x = 1/2
⇒
2(2x - 4) = 3x
⇒
4x - 8 = 3x
⇒
x = 8
∴ First number = 2 × 8
= 16
∴
Second number = 3 × 8 = 24
0
Updated: 1 month ago
At what rate of compound interest per annum will a sum of Tk. 1600 becomes Tk. 2304 in 2 years?
Created: 1 month ago
A
20%
B
15%
C
12%
D
30%
Question: At what rate of compound interest per annum will a
sum of Tk. 1600 becomes Tk. 2304 in 2 years?
Solution:
Principal, P = 1600 টাকা
Amount, A = 2304 টাকা
Time, n = 2 years
Rate, r = ?
We know,
A = P × (1 + r/100)n
⇒
2304 = 1600 × (1 + r/100)2
⇒
(1 + r/100)2 = 2304/1600
⇒
(1 + r/100) = 48/40 [উভয়পাশে
বর্গমূল করে]
⇒
1 + r/100 = 6/5
⇒
r/100 = 6/5 - 1
⇒
r/100 = (6 - 5)/5
⇒
r/100 = 1/5
⇒
r = 100/5
∴
r = 20
∴ Interest rate 20%
0
Updated: 1 month ago
What is the compound amount of Tk. 3200 for 2 years at a rate of interest 5% per annum?
Created: 1 month ago
A
Tk. 3500
B
Tk. 3528
C
Tk. 3640
D
Tk. 3568
Question: What is the compound amount of Tk. 3200 for 2
years at a rate of interest 5% per annum?
Solution:
Given,
Principal, P = 3200
Rate, r = 5% = 5/100 = 1/20
Time, n = 2 years
We know,
A = P(1 + r)n
= 3200 × (1 + 1/20)2
= 3200 × (21/20)2
= (3200 × 21 × 21) / (20 × 20)
= (3200 × 441) / 400
= 1411200 / 400
= 3528
∴ The compound amount is Tk. 3528.
0
Updated: 1 month ago
