It takes 30 minutes to empty a half-full tank by draining it at a con...
Given in the question that; V
half = 30(s)
Let us take drawing rate = s
Total volume = 60 S tank
(s1)(10) – (s)10 = 30s
s1(s) – s = 3s
s1 = 4s
s1 = 4 times the drawing rate.
It takes 30 minutes to empty a half-full tank by draining it at a con...
Problem Analysis:
Let's assume that the draining rate is D liters/minute and the rate at which water is pumped in is P liters/minute.
Given:
- It takes 30 minutes to empty a half-full tank by draining it at a constant rate.
- It is decided to simultaneously pump water into the half-full tank while draining it.
- The tank needs to be fully filled in 10 minutes.
Approach:
To solve this problem, we can use the concept of work.
Work Done by Draining:
- The work done by draining is equal to the product of the draining rate and the time taken to drain the tank.
- Work done by draining = D * 30 (since it takes 30 minutes to empty the half-full tank)
Work Done by Pumping:
- The work done by pumping is equal to the product of the pumping rate and the time taken to fill the tank.
- Work done by pumping = P * 10 (since it takes 10 minutes to fill the tank)
Total Work:
- The total work done is the sum of the work done by draining and the work done by pumping.
- Total work = D * 30 + P * 10
Since the tank is half-full at the beginning, the total work done should be equal to filling a full tank.
Equation:
D * 30 + P * 10 = 1 (since the total work done should be equal to filling a full tank)
Solving for P:
Let's solve the equation for P to find the rate at which water has to be pumped in.
D * 30 + P * 10 = 1
P * 10 = 1 - D * 30
P = (1 - D * 30) / 10
Simplification:
P = (1 - 3D) / 10
Comparing Options:
We need to find the rate at which water has to be pumped in, which is represented by P.
Comparing the equation P = (1 - 3D) / 10 with the given options:
a) P = 4D, which is not equivalent to (1 - 3D) / 10
b) P = 3D, which is not equivalent to (1 - 3D) / 10
c) P = 2.5D, which is not equivalent to (1 - 3D) / 10
d) P = 2D, which is not equivalent to (1 - 3D) / 10
None of the options match the equation (1 - 3D) / 10, so none of the given options are correct.
Therefore, the correct answer cannot be determined from the given options.