Question

plzz...help its urgent...❣️
plzz solve it...plzz...its too urgent...
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Answer 1

Answer:

let the speed of the boat in stream be xkm/h and ykm/h be the speed of stream

speed of boat in downstream = x+y

speed of boat in upstream = x-y

using 1st condition

30/ x-y + 44/ x+y = 10

22/ x+y + 15/ x-y = 5 --(1)

using 2nd condition

40/x-y + 55/x+y =13

11/x+y + 8/x-y=13/5 --(2)

multiplying eq--(2) by 2

we get,

22/x+y + 16/x-y =26/5 --(3)

subtracting eq(1) from eq(3)

22/ x+y + 15/ x-y = 5

- ( 22/x+y + 16/x-y = 26/5 )

____________________________

= - 1/x-y = -1/5

x-y = 5 --(4)

putting thisin eq (2)

11/x+y + 8/5=13/5

we get x+y = 11 --(5)

Adding eq (4) and eq (5)

x-y = 5

x+y = 11

___________________________

2x = 16

x = 8

put this in eq (5)

8 + y = 11

y = 3

speed of boat in downstream = x+y

= 8+3

= 11

speed of boat in upstream = x-y

= 8-3

= 5

Answer 2

Solution :

let the speed of boat =xkm/hr

speed of stream =ykm/hr

speed of boat downstream =x+ykm/hr

speed of boat upstream x−ykm/hr

time taken t1=30x−yhrs

t2=44x+y hrs

t1+t2=10hrs

30x−y+44x+y=10 eqn(1)

t3=40x−yhrs

t4=55x+y

=40x−y+55x+y=13 eqn(2)

let 1x−y=A&1x+y=B

30A+44B=10

40A+55B=13

B=13−40A55

30A+44(13−40A55)=10

15A+(22⋅(13−40A55))=5

75A+2(13−40A)=5

75A+26−80A=25

A=15

B=13−40⋅1555=13−855=111

1x−y=15

1x+y=111

x−y=5

x=5+y

& x+y=11

5+y+y=11

5+2y=11

y=62=3km/hr

x=3+5=8km/hr

Inni gandi handwritting...xD