Question

a Boat takes 8 hours to travel 30 km upstream and downstream 36 kilometre but I take 10 hour to travel 36 km upstream and 48 kilometre downstream find the speed of boat water speed of the steam ​

Answer 1

Answer:

put time as well as km for finding the value

Answer 2

Answer:

boat speed = 9km/h

stream = 3km/h

Step-by-step explanation:

boat speed = x

stream = y

upstream = x-y

downstream = x+y

t = d/v

8 = 30/x-y +36/x+y ...............(i)

10 = 36/x-y + 48/x+y ..............(ii)

let 1/x-y = a and 1/x+y = b

30a + 36b = 8 multiple by 6

180a + 216b = 48 ...............(iii)

36a + 48b = 10 multiple by 5

180a + 240b =50 ................(iv)

180a + 216b = 48

180a +240b = 50

- - -

________________

-24b = -2

24b = 2

b =1/12

30a + 36b = 8

put the value of (b)

30a + 36×1/12 = 8

30a + 3 = 8

30a = 5

a = 1/6

a = 1/x-y = 1/6

x-y = 6 ..............(v)

b = 1/x+y = 1/12

x+y = 12 .............(vi)

adding (v) and (vi)

(x-y) + (x+y) = 6 + 12

x-y+x+y = 18

2x = 18

x = 9

x + y = 12

9 + y = 12

y = 12-9

y = 3

boat speed = 9

stream = 3

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