Mathematics, 30.01.2020 17:01 alyo31500

Sun, a kayaker, paddles 8 miles upstream (against the current) in 2 hours. returning to her original location, she paddles downstream (with the current) the same distance in 1 hour. the equations represent x, the paddling speed, and y, the speed of the current.2(x – y) = a
b(x + y) = 8

which are true? check all that apply.

a = 8

b = 8

a = 1

b = 1

a = b

Answers: 2

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Answers

Answer from: neonaandrews10

a=8 and b=1

Step-by-step explanation:

Given : Sun, a kayaker, paddles 8 miles upstream (against the current) in 2 hours. Returning to her original location, she paddles downstream (with the current) the same distance in 1 hour. The equations represent x, the paddling speed, and y, the speed of the current.

2(x - y) = a and b(x + y) = 8

To find : Which are true?

Solution :

If x represents the paddling speed, and y represents the speed of the current.

The relative speed in upstream is x-y

Relative time in downstream= x+y

A kayaker, paddles 8 miles upstream (against the current) in 2 hours.

$\text{Distance}=\text{Speed} \times \text{Time}$

$8=(x-y)\times 2$

Comparing with 2(x - y) = a

We get, a=8

Returning to her original location, she paddles downstream (with the current) the same distance in 1 hour.

$\text{Distance}=\text{Speed} \times \text{Time}$

$8=(x+y)\times 1$

Comparing with b(x + y) = 8

We get, b=1

Thus, a=8 and b=1

Therefore, Option 1 and 4 is correct.

Answer from: Quest

the correct option is 2.

step-by-step explanation:

according to the given information triangle abc is a right angle triangle with right angle at a. segment ab is 5 and segment ac is 7. point d is on segment bc and angles adb and adc are right angles.

it is given that triangles abd, cad, and cba are similar.

two triangles are similar if their corresponding sides are proportional.

in triangle cba, using pythagoras theorem

$ab^2+ac^2=bc^2$

$ab^2+ac^2=x^2$ )

triangle abd and cba are similar,

$\frac{ab}{bc}=\frac{bd}{ab}$

$ab^2=bc\cdot bd$

$25=bc\cdot bd$ (2)

triangle cad and cba are similar,

$\frac{ac}{bc}=\frac{cd}{ac}$

$ac^2=bc\cdot dc$

$7\times 7=bc\cdot dc$

$49=bc\cdot dc$ )

using (1), (2) and (3), we get

$25+49=x^2$

$74=x^2$

hence proved.

therefore option 2 is correct.

Answer from: Quest

the population of other specie of birds will decline or other specie of birds will find some alternate source of food to survive.

explanation:

according to the competitive exclusion principle, which is also known as gause's law, two specie living in the same niche and feeding on the same resource cannot co-exist stably.

as we have well studied the theory of natural selection which states that only those organisms survive which have better tendency to compete for food and adapt to the environmental conditions.

coming towards the question, what wi ll happen when one species outcompetes the other for the small fish , the other specie will not get enough food and will start to die or decline in population. eventually either other specie needs to find another alternative food source for itself or migrate at some other location where there is less competition otherwise it will just not exist anymore at that niche.

hope it !

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Sun, a kayaker, paddles 8 miles upstream (against the current) in 2 hours. returning to her original...

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