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?
A
Tk. 129
B
Tk. 121
C
Tk. 118
D
Tk. 132
উত্তরের বিবরণ
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: 2 months ago
How much water should be added to 80 liters of pure milk to gain extra 20% profit when selling the mixture at the price of pure milk?
Created: 3 weeks ago
A
6 liters
B
12 liters
C
8 liters
D
16 liters
Question: How much water should be added to 80 liters of pure milk to gain extra 20% profit when selling the mixture at the price of pure milk?
Solution:
Let’s assume,
Price of pure milk per liter = 100 Taka
So, the price of 50 liters of pure milk = 100 × 80 = 8000 Taka
Now assume,
Water added to the milk = x liters
Then the total quantity of the milk-water mixture = (80 + x) liters
Since the mixture is sold at the price of pure milk,
The selling price of (80 + x) liters = 100(80 + x) Taka
According to the question,
100(80 + x) = 8000 + 8000 of 20%
⇒ 8000 + 100x = 8000 + {8000 × (20/100)}
⇒ 8000 + 100x = 8000 + 1600
⇒ 8000 - 8000 + 100x = 1600
⇒ 100x = 1600
⇒ x = 1600/100
⇒ x = 16
∴ Amount of water to be added = 16 liters
0
Updated: 3 weeks ago
সরল সুদের হার শতকরা কত টাকা হলে যে কোনো মূলধন ৮ বছরে সুদে-আসলে তিনগুণ হবে?
Created: 5 months ago
A
১২.৫০ টাকা
B
২০ টাকা
C
২৫ টাকা
D
১৫ টাকা
প্রশ্ন: সরল সুদের হার শতকরা কত টাকা হলে যে কোনো মূলধন ৮ বছরে সুদে-আসলে তিনগুণ হবে?
সমাধান:
ধরি,
আসল P = ১০০ টাকা
সুদাসল A =১০০ × ৩ = ৩০০টাকা
সুদ I =(৩০০ - ১০০) টাকা = ২০০টাকা
আমরা জানি
I = Pnr
r = I/Pn
সুদের হার r = (১০০ × ২০০)/(১০০ × ৮)
= ২৫%
0
Updated: 5 months ago
How many years will Tk. 1500 need at 4% simple interest to earn the same interest as Tk. 2000 earns in 3 years at 5% simple interest?
Created: 2 months ago
A
4 years
B
5 years
C
6 years
D
8 years
Solution:
Interest from Tk. 2000 in 3 years at 5%:
SI = (P × R × T)/100
= (2000 × 5 × 3)/100
= 300 Tk.
Now,
Tk. 1500 to Produce the Same Interest (Tk. 300) at 4%:
Principal, P = Tk. 1500
Interest, SI = Tk. 300
Interest Rate, R = 4%
Time, T = ? years
SI = PRT/100
⇒ T = (SI × 100)/(P × R)
⇒ T = (300 × 100)/(1500 × 4)
⇒ T = 30000/6000
∴ T = 5 years
0
Updated: 2 months ago
