Question

A boat goes 30 km upstream and 44 km downstream in 10 hrs. In 13 hrs, 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

Step-by-step explanation:

let speed boat in still water be x km/h and speed of stream be y km/h

speed upstream = (x - y) km/h

speed downstream = (x + y) km/h

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

30/x - y + 44/ x + y = 10 => 30a + 44b = 10 => 120a + 176b = 40

40/x - y + 55/ x + y = 13 => 40a + 55b = 13 => 120a + 165b =39

On subtracting, we get,

b = 1/11

.°. 30a + 4 = 10 => 30a = 6 => a = 1/5

.°. x - y = 5 and x + y = 11

On solving, we get,

X = 8 , Y = 3

.°. Speed boat in still water = 8 km/h

And, Speed of Stream = 3 km/h

Answer 2

Step-by-step explanation:

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I think this helps you....

the speed of ⛵ in still water is 8km/h .

the speed of stream is 3km/h .

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