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Katyanochek1 [597]
2 years ago
15

The speed of a stream is 3 km per hour. A boat travels upstream 12 km and then returns to its original position downstream along

the same route. If the speed of the boat in still water is 9 km per hour, what is the average speed of the boat for the entire round trip?
Mathematics
1 answer:
svlad2 [7]2 years ago
7 0

Answer:

7 km

Step-by-step explanation:

let the speed of boat in still water is x km/hr. 

given speed of stream is 3 km/hr. 

then speed of boat upstream = ( x - 3) km/hr

speed of boat downstream = (x + 3 ) km/hr 

Distance travelled upstream = 4 km

time taken to travel upstream = distance travelled upstream / speed of boat 

upstream

= 4 / (x - 3 ) .............(1) 

Distance travelled downstream = 10 km

time taken to travel downstream = distance travelled downstream / speed of boat 

downstream

= 10 / (x + 3) ............(2)

given that boat takes same time to travel upstream and downstream.i.e; (1) & (2) are equal

i.e. 4/(x-3) = 10/ (x + 3 ) 

4 * (x +3 ) = 10 * (x- 3)

4x + 12 = 10x - 30

12 + 30 = 10x -4x 

42 = 6x 

x = 42 / 6 = 7. 

i.e speed of boat in still water is 7 km/hr.

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Answer: 9 1/16

nine and one sixteenth

Step-by-step explanation:

Substitute x = 3 and y = 4 into the equation:

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Then solve using the order BEDMAS (brackets, exponenets, division, multiplication, addition, subtraction).

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-X + 2y= -3 and -8x — 3y= -5
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Answer:

x=1, y=-1. (1, -1).

Step-by-step explanation:

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-8x-3y=-5

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8x-16y=24

-8x-3y=-5

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-19y=19

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4 0
2 years ago
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Answer:

3

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Given that a manager is considering three new machines for filling boxes of cereal at a processing plant. Each of the three machines is assigned to 10 randomly selected employees

Here the treatments are the no of machines. i.e. three machines are three treatment.

After selecting treatments 25 boxes using each machine is recorded.

Hence this is a one factor anova with three factors namely three machines affecting the result

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Creat an equation for a cubic function, in standard form, that has x- intercept given by the set {-3,1,7} and which passes throu
prohojiy [21]

Given :

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y= a(x+3)(x-1)(x-7)               ... equation (1)

Step 2: substitute x an y with the point through which it passes,

54=a((-2)+3)((-2)-1)((-2)-7)

54 = 27a

∴ a=2

Step 3: Now, substituting value of a in equation (1), we have

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Semenov [28]

Answer: Ann read 34 pages that day

Step-by-step explanation:

Ann reads 10 pages of her book everyday

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With 12 free minutes that day we do the following:

Multiply 12 by 2 to get the number of pages she reads in that free time which equals 24.

Then we add that 24 to the 10 pages she will read regardless.

Which leaves us with 34 pages.

Hope This Helps! :)

5 0
3 years ago
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