If 'p' is the precipitation, 'a' is the area represented by a rainguage, and n is the number of raingauges in a catchment area, then the weighted mean rainfall is

If 'p' is the precipitation, 'a' is the area represented by a rainguag

1.	If 'p' is the precipitation, 'a' is the area represented by a rainguage, and n is the number of raingauges in a catchment area, then the weighted mean rainfall is
A.	<img src="/_files/images/civil-engineering/upsc-civil-service-exam-questions/73-455-1.png">
B.	<img src="/_files/images/civil-engineering/upsc-civil-service-exam-questions/73-455-2.png">
C.	<img src="/_files/images/civil-engineering/upsc-civil-service-exam-questions/73-455-3.png">
D.	<img src="/_files/images/civil-engineering/upsc-civil-service-exam-questions/73-455-4.png">
Answer» D. <img src="/_files/images/civil-engineering/upsc-civil-service-exam-questions/73-455-4.png">