Question

A boat covered 30 km in the opposite direction and 44 km in the direction of stream in 10 hours, and in 13 hours it travelled 40 km in the opposite direction and 55 km in the direction of stream. The speed of boat in the constant water is

Answer 1

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THANKYOU YOU ASKING
QUESTION
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HERE YOUR SOLUTION
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Φ the speed of the boat be x and the speed of the strean be y

ΦThen speed of the boat in upstream = (x-y) kmph

ΦThe speed of the boat in downstream = (x+y) kmph

THEN
30/(x-y) + 44/(x+y) = 10

1/(x-y) = a and 1/(x+y) = b

It implies 30a +44b = 10.......(i)

Similarly
40a+55b = 13........(ii)

Multiplying
(i) by 4 and (ii) by 3

120a + 176b = 40...........(iii)

120a + 165b = 39..........(iv)

Subtracting
(iv) from (iii)

11b =1
Hence
b = 1/11

Putting b in (i)

30a + 4 = 10
a = 1/5

Now
b = 1/x+y = 1/11

or
x+y = 11..........(v)

and a = 1/x-y = 1/5

or x-y = 5...........(vi)

Adding
(v) and (vi)

2x = 16
x = 8

Putting x in (v)

..8+y = 11
y = 3


the speed of the boat = 8kmph

and speed of the stream = 3kmph

this is correct answer

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Answer 2

question hi sahi nahi h

Step-by-step explanation:

8 km per hour ayega bas itni baat h