At Deoprayag, (Garhwal, UP ), river Alaknanda mixes with the river Bhagirathi and becomes river Ganga. Suppose Alaknanda has a width of 12 m, Bhagirathi has a width of 8 m and Ganga has a width of 16 m. Assume that the depth of water is same in the three rivers. Let the average speed of water in Alaknanda is 20 km h-1, and in Bhagirathi be 16 km h-1 . Find the average speed of water in the river Ganga 

Asked by Paresh | 2nd Jan, 2016, 09:01: PM

Expert Answer:

begin mathsize 12px style Given colon Width space of space Bhagirathi comma space straight h subscript straight B equals 8 space straight m Width space of space Alaknanda comma space straight h subscript straight A equals 12 space straight m Width space of space Ganga comma space straight h subscript straight G equals 16 space straight m Average space speed space of space water space in space Alaknanda comma space straight v subscript straight A space equals space 20 space km divided by straight h Average space speed space of space water space in space Bhagirathi comma space straight v subscript straight B space equals space 16 space km divided by straight h Let space straight d space be space the space depth space of space the space three space rivers Here comma Volume space of space water space discharged space from space Alaknanda space plus space Volume space of space water space discharged space from space Bhagirathi space equals space Volume space of space water space flow space in space Ganga rightwards double arrow straight v subscript straight A cross times straight d cross times straight h subscript straight A plus straight v subscript straight B cross times straight d cross times straight h subscript straight B equals straight v subscript straight G cross times straight d cross times straight h subscript straight G rightwards double arrow 20 cross times 12 plus 16 cross times 8 equals straight v subscript straight G cross times 16 rightwards double arrow straight v subscript straight G cross times 16 equals 368 rightwards double arrow straight v subscript straight G equals 368 over 16 equals 23 space km divided by straight h end style

Answered by Priyanka Kumbhar | 4th Jan, 2016, 01:21: PM