A maths question....Plz answer....Thanks.......?

Solve as a proportional problem

30/(x - 4) = 60/(x + 4)

The Means = 60(x - 4)

The Extremes = 30(x + 4)

The equation

60(x - 4) = 30(x + 4)

The distributive property on both sides of the equation''

60x - 240 = 30x + 120

Transpose 30x

60x - 240 - 30x = 30x + 120 - 30x

Collect like terms

30x - 240 = 120

Transpose 240

30x - 240 + 240 = 120 + 240

30x = 360

Divide both sides of the equation by 30

30x / 30 = 360 / 30

x = 360/30

x = 12. . .←km/hr

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The speed of the boad in still water is 12 Km/hr

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I don't know but I'll have a go

If the boat goes up stream for one hour and covers 30 K it averages 30 kph.

Down stream for 60 K it averages 60 kph.

difference of 30 kph

Thus the difference made by the river will be 15kph.

If the rivers speed is 4 kph

that would make the boats speed 11kph.

Would be my guess

Let the speed in still water is "s", then distance travelled=speedXtime, or t=d/s, now t=(30/s-4)

and t=60/(s+4), or

30/(s-4)=60/(s+4)

1/(s-4)=2/(s+4)

s+4=2s-8

s(speed in still water)=12 Km/hour

Dave's original # of pencils=d Bob's original # of pencils=b ~~~~~~~~ d=2b d=34-8 2b=34-8 2b=26 b=13 Before Dave bought 8 more pencils, Dave had twice the amount of pencils Bob had. So twice Bob's amount would be Dave's amount. After Dave buys 8 more pencils, he has 34. So right now Dave has twice the amount of pencils as Bob plus eight. If we subtract 8 pencils from Dave's current total (34), Dave will have twice as many pencils as Bob. When we do this we get 26. So we now know that half of 26 is the amount of pencils Bob has. So the total number of pencils that Bob has is 13.

8 kph?

seriously i dont know

just a guess

idk even what a km is

2km per hour?

7.5 kmph

i dunno