A pipe of 2 inch diameter fills a water tank in one hour . If the diameter of the pipe is 4 inch in what time will the pipe fill the same tank?
A
10 minutes
B
15 minutes
C
30 minutes
D
45 minutes
Correct Answer: 15 minutes
Diameter দিয়ে বৃত্তের Area equation = πd24 যদি diameter double হয়, তবে Area বর্গ আকাড়ে বাড়ে। so time = 60min4 = 15 min