Two pipes can fill a tank in 25 and 30 minutes respectively and a wast...
Solution:
Let the capacity of the tank be x gallons.
The given time taken by the first pipe to fill the tank is 25 minutes. Hence, the rate of filling of the first pipe is:
1/25 tank/minute
Similarly, the rate of filling of the second pipe is:
1/30 tank/minute
The waste pipe empties 3 gallons per minute. Hence, the rate of emptying of the waste pipe is:
3 gallons/minute
Let the rate of filling of all the three pipes working together be y tank/minute.
According to the question, all the three pipes working together can fill the tank in 15 minutes. Hence, we can write:
y * 15 = x
Simplifying the above equation, we get:
y = x/15
Now, we can write the following equation based on the rates of filling and emptying:
1/25 + 1/30 - 3/x = y
Substituting the value of y, we get:
1/25 + 1/30 - 3/x = x/15
Simplifying the above equation, we get:
x = 450
Therefore, the capacity of the tank is 450 gallons.
Answer: Option B (450 gallons)