Question

a boqt goes 30 km upstream and 44 km downstream in 10 hours 13 hours it can go 40 km upstream and 55 km downstream determine the speed of the stream and that of the boat in still water​

Answer 1

Answer:

toh boat chalegi pani m khatam ho gyi paani m

Answer 2

Step-by-step explanation:

Let the speed of the stream =x km/hr

Let the speed of the boat in still water =y km/hr

Upstream speed =y−x km/hr

Downstream speed =y+x km/hr

time=

speed

distance

The boat goes 30 km upstream and 44 km downstream in 10 hours.

Time taken =

y−x

30

+

y+x

44

10=

y−x

30

+

y+x

44

................. (1)

The boat goes 40 km upstream and 55 km downstream in 13 hours.

Time taken =

y−x

40

+

y+x

55

13=

y−x

40

+

y+x

55

.................. (2)

Let

y−x

1

=u

and

y+x

1

=v

From (1) and (2),

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

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

Multiply equation (3) with 4 and equation (4) with 3,

120u+176v=40 ........... (5)

120u+165v=39 ........... (6)

subtract equation (6) from (5),

176v−165v=40−39

11v=1

v=

11

1

⇒

y+x

1

=

11

1

y+x=11 .......................... (7)

From equation (3),

30u=10−44v

30u=10−44×

11

1

30u=10−4=6

u=

5

1

y−x

1

=

5

1

⇒y−x=5 .................. (8)

Adding (7) and (8), we get,

2y=16

y=8

From equation (7),

x=11−y

x=11−8=3