Question

A boat covers 25 km upstream and 44 km downstream in 9 hours also it covers 15 km upstream and 22 km downstream in 5 hours find the speed of boat in still water and that of the stream

Answer 1

Speed of boat in still water=x km/hr
Speed of stream=y km/hr
Speed of upstream=x-y km/hr
Speed of downstream=x+y km/hr
Let 1/(x-y)=a and 1/(x+y)=b
Time to go 25km up and 44 down=9
25a+44b=9----->(1)
Time to go 15km up and 22km down=5
15a+22b=5------>(2)
(2) × 2=> 30a+44b=10------>(3)
(3)-(1)=>5a=1
a=1/5
1/(x-y)=1/5
x-y=5---->(4)
Putting a=1/5 in (1),
5+44b=9
44b=4
b=1/11
1/(x+y)=1/11
x+y=11---->(5)
(4)+(5)=>2x=16
x=8
y=3
Speed of boat in still water=8km/hr
Speed of stream=3km/hr
(This took me an eternity to type so please mark as brainliest)

Answer 2

Answer:The speed of boat in still water is 8km/h

And the speed of the stream is 3km/h

Step-by-step explanation:

Speed of boat in still water=x km/hr

Speed of stream=y km/hr

Speed of upstream=x-y km/hr

Speed of downstream=x+y km/hr

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

Time to go 25km up and 44 down=9

25a+44b=9----->(1)

Time to go 15km up and 22km down=5

15a+22b=5------>(2)

(2) × 2=> 30a+44b=10------>(3)

(3)-(1)=>5a=1

a=1/5

1/(x-y)=1/5

x-y=5---->(4)

Putting a=1/5 in (1),

5+44b=9

44b=4

b=1/11

1/(x+y)=1/11

x+y=11---->(5)

(4)+(5)=>2x=16

x=8

y=3

Speed of boat in still water=8km/hr

Speed of stream=3km/hr