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 8m and Ganga has a width of 16m. Assume that the depth of water is same in the three rivers. Let the average speed of water in Alaknanda be `20 kmh^-1` and in Bhagirathi be `16 kmh^-1`. Find the average speed of water in the river Ganga.

Answer

A, B, C

Explanation

Volume of water discharged from AlakN/Anda+Volum of water discharged from Bhagirathi= Volume of water Flow in Ganga.
let drarr `depth of 3 rivers
`rarr V_axxdxx12+V_Bxxdxx8`
`rarr V_Gxxdxx16`
[From equation of continuity]
`rarr 20xx12+16xx8=V_Gxx16`
`rarr V_Gxx16=368`
`rarr V_G=368/16`
`-=23km/hr`