A 42-liter mixture contains milk and water in a 3 : 4 ratio. How much milk should be added to the mixture to make the ratio equal?
A
7 liters
B
4 liters
C
6 liters
D
8 liters
উত্তরের বিবরণ
Question: A 42-liter mixture contains milk and water in a 3 : 4 ratio. How much milk should be added to the mixture to make the ratio equal?
Solution:
The ratio of milk to water is 3 : 4
Total portion = 3 + 4 = 7
Quantity of milk = 42 × (3/7) = 18 liters.
Quantity of water = 42 × (4/7) = 24 liters.
Let,
Quantity of milk to be added = x liters
According to the question,
(18 + x) : 24 = 1 : 1
⇒ (18 + x)/24 = 1/1
⇒ 18 + x = 24
⇒ x = 24 - 18
⇒ x = 6
∴ Quantity of milk to be added = 6 liters
0
Updated: 1 month ago
The speed of a boat in still water is 9 km/h. The time it takes to travel downstream is half the time it takes to travel upstream. What is the speed of the stream?
Created: 1 month ago
A
3 km/h
B
2.5 km/h
C
4 km/h
D
3.5 km/h
Question: The speed of a boat in still water is 9 km/h. The time it takes to travel downstream is half the time it takes to travel upstream. What is the speed of the stream?
Solution:
Let the speed of the current be = x km/h
Then,
Downstream speed = (9 + x) km/h
Upstream speed = (9 - x) km/h
According to the question:
(9 + x) = 2(9 - x)
⇒ 9 + x = 18 - 2x
⇒ 2x + x = 18 - 9
⇒ 3x = 9
⇒ x = 9/3
⇒ x = 3
∴ Speed of the stream = 3 km/h
0
Updated: 1 month ago
বার্ষিক ১২% মুনাফায় কত বছরের ১০০০০ টাকার মুনাফা ৪৮০০ টাকা হবে?
Created: 2 days ago
A
৩ বছর
B
৪ বছর
C
৫ বছর
D
৬ বছর
আমরা জানি, I= prn
n = I/pr
যেখানে মুনাফা, I = ৪৮০০ টাকা, ও মূলধন p, = ১০০০০ টাকা,
মুনাফার হার r = ১২%, সময় n = ?
∴ সময় = মুনাফা/(আসল×মুনাফার হার)
=৪৮০০/{১০০০০×(১২/১০০)} বছর
= (৪৮০০×১০০)/(১০০০০×১২) বছর
= ৪ বছর
∴ সময় লাগবে ৪ বছর
0
Updated: 2 days 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: 3 months 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: 3 months ago
