Question

9. A boat goes 16 km upstream and 28 km downstream in 7 hrs. Also it covers 12 km upstream
and 36 km downstream in the same time. Find the speed of the boat upstream and
downstreamn.
in and northyhycar If he covers 400 km by train and​

Answer 1

Answer:

4,12

Step-by-step explanation:

Let speed of the boat in still water =x km/hr, and

Speed of the current =y km/hr

Downstream speed =(x+y) km/hr

Upstream speed =(x−y) km/hr

T=

S

D

x+y

24

+

x−y

16

=6 .......(1)

x+y

36

+

x−y

12

=6 .......(2)

Put

x+y

1

=u and

x−y

1

=v the above equation becomes,

24u+16v=6

Or, 12u+8v=3 ... (3)

36u+12v=6

Or, 6u+2v=1 ... (4)

Multiplying (4) by 4, we get,

24u+8v=4v … (5)

Subtracting (3) by (5), we get,

12u=1

⇒u=

12

1

Putting the value of u in (4), we get, v=

4

1

⇒

x+y

1

=

12

1

and

x−y

1

=

4

1

⇒x+y=12 and x−y=4

Thus, speed of the boat upstream =4 km/hr

Speed of the boat downstream =12 km/hr. Hope it helps..Mark brainlist...