At what rate of compound interest per annum will a sum of Tk. 5000 become Tk. 7200 in 2 years?
A
5%
B
10%
C
15%
D
20%
উত্তরের বিবরণ
সমাধান:
দেওয়া আছে,
মূলধন (Principal), P = 5000 টাকা
চক্রবৃদ্ধি মূল (Compound Amount), C = 7200 টাকা
সময় (Time), n = 2 বছর
মুনাফার হার (Rate), r = ?
আমরা জানি,
চক্রবৃদ্ধি মূল, C = P(1 + r/100)n
⇒ 7200 = 5000(1 + r/100)2
⇒ (1 + r/100)2 = 7200/5000
⇒ (1 + r/100)2 = 72/50
⇒ (1 + r/100)2 = 36/25
⇒ (1 + r/100) = 6/5
⇒ (100 + r)/100 = 6/5
⇒ (100 + r) = 600/5
⇒ r = 120 - 100
∴ r = 20
সুতরাং, বার্ষিক চক্রবৃদ্ধি সুদের হার 20%।
0
Updated: 22 hours ago
A bank offers 5% compound interest calculated half-yearly. A customer deposits Tk. 1600 on 1st January and another Tk. 1600 on 1st July of the same year. How much interest will he earn at the end of the year?
Created: 1 month ago
A
Tk. 129
B
Tk. 121
C
Tk. 118
D
Tk. 132
Solution:
Here,
Half-yearly interest rate = 5% ÷ 2 = (5/2)%
Now,
The first deposit of Tk. 1600 was made on 1st January.
It stays for 12 months, so it earns interest twice, once after 6 months, and again after 12 months.
So, it earns interest for 2 times (i.e., 2 half-years).
∴ A1 = P(1 + r/100)n
= 1600 × {1 + 5/(2 × 100)}2
= 1600 × {1 + (1/40)}2
= 1600 × (41/40) × (41/40)
= 1600 × 1681/1600
= 1681
Now,
The second deposit of Tk. 1600 was made on 1st July.
It stays for 6 months, so it earns interest only once (1 half-year).
∴ A2 = P(1 + r/100)n
= 1600 × (1 + 1/40)1
= 1600 × (41/40)
= 1640
Total amount = 1681 + 1640 = 3321
Total money deposited = 1600 + 1600 = 3200
∴Interest earned = 3321 - 3200 = Tk. 121
∴ The customer would have gained Tk. 121 by way of interest.
0
Updated: 1 month ago
A person took a loan of Tk. 2500 with simple interest for as many years as the rate of interest. If they paid Tk. 1600 as interest at the end of the loan period, what was the r10%ate of interest?
Created: 22 hours ago
A
5%
B
6%
C
8%
D
10%
ধরি, সুদের হার = r%
যেহেতু সময় এবং সুদের হার সমান,
∴ সময়, n = r বছর
আসল (P) = 2500 টাকা
মোট সুদ (I) = 1600 টাকা
আমরা জানি,
সরল সুদ, SI = (P × r × n)/100
⇒ 1600 = (2500 × r × r)/100 [এখানে, n = r]
⇒ 1600 = 25 × r2
⇒ r2 = 1600/25
⇒ r2 = 64
⇒ r = √64
⇒ r = 8
∴ সুদের হার ছিল 8%।
0
Updated: 22 hours ago
Find the rate of discount being given on a shirt whose selling price is Tk. 420 after deducting a discount of Tk. 80 on its marked price.
Created: 6 days ago
A
12%
B
8%
C
16%
D
10%
Question: Find the rate of discount being given on a shirt whose selling price is Tk. 420 after deducting a discount of Tk. 80 on its marked price.
Solution:
দেওয়া আছে,
বিক্রয়মূল্য = 420 টাকা
কমিশন = 80 টাকা
∴ গায়ে লিখা দাম = (420 + 80) টাকা
= 500 টাকা
500 টাকায় কমিশন দেয় 80 টাকা
∴ 1 টাকায় কমিশন দেয় 80/500 টাকা
∴ 100 টাকায় কমিশন দেয় (80 × 100)/500 টাকা
= 16 টাকা
0
Updated: 6 days ago
