a boat goes 24km upstream and 28km downstream in 6hrs . it goes 30km upstream and 21 km downstream in 6 1/2 hrs . find the speed of boat in still water and also speed of stream
let the speed of the boat upstream =(x-y)km/hr
and the speed of the boat downstream=(x+y)km/hr
A.T.Q
24/(X-Y)+28/(X+Y)=6 -(1.) 30/(X-Y)+21/(X+Y)=61/2 -(2.)
LET 1/(X-Y)=U &1/(X+Y)=V
24U+28V=6 -(1)
30U+21V=61/2 -(2.)
BY ELIMINATION PROCESS-:
720U+840