Question

The boat goes 30km upstream and 44km downstream in 10 hours. it can go 40km upstream andb55km downstream. determine the speed of stream and that of the boat in still water

Answer 1

it will help u.................................

Answer 2

Answer:

Step-by-step explanation:

=let the speed of the boat in still water bexkm/he and speed of the stream be ykm/hr

Speed of upstram stream of boat =(x-y) km/hr

Time=distance /speed

30km upstream, t1 =30/x-y

44 km downstream, =t2=44/x+y

30/x-y+44/x+y=10.....1

40/x-y+5/x+y=13...2

1/x-y=u,1/x+y=v

30u+44v=10.......3

40u+55v=13........4

Using cross multiple method

u/44(-13)-55(-10)=v/40(-10)-30(-13)=1/30(55)-44(40)

u/-22=v/-10=1/-110

u=1/5,v=1/11

1/x-y=1/5 and 1/x+y=1/11

x-y=5 and x+y=11

2x=16

x=8

2y=6

y=3

Hence, the speed of boat in still water is 8km/hr and the speed of the stream is 3km/hr.