1.

A boat goes 12 km upstreamand 40 km downstream in 8 hours It can go 16 km upstream and 32 km downstream in the same time .Fins the speed of the boat in still waterand the speed of the stream

Answer»

Step-by-step EXPLANATION:

LET SPEED OF BOAT=x KM/H

SPEED OF STREAM=y KM/H

WHERE x>y

SPEED IN UPSTREAM=X-Y

SPEED IN DOWNSTREAM=X+Y

TIME=DISTANCE/SPEED

8=12/X-Y + 40/X+Y___(1)

8=16/X-Y+32/X+Y___(2)

LET 1/X-Y=a

1/X+Y=b

8=12a+40b___(3)

8=16a+32b___(4)

MULTIPLY EQ 3 by 4 and EQ 4 by 3 and subtract 3 from 4

48a+96b=24

-(48a+160b=32)

=(-64b=(-8))

B=1/8

Putting value of B in EQ 3

8-5=12a

A=1/4

Now,

a=1/x-y

x-y=4___(5)

b=1/x+y

x+y=8__(6)

ADD (5) AND (6)

2x=12

x=6

Put value of x in (6)

y=2

So

SPEED OF BOAT IS 6KM/H

AND SPEED OF STREAM IS 2KM/H

MARK ME AS BRAINLIEST


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