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2 years ago

Cant find the answer

Mathematics

1 answer:

dedylja [7]2 years ago

7 0

Answer:

Carter family = 25 hours

Davis family = 31 hours

Step-by-step explanation:

Let's say the number of hours the Carter family used their sprinkler is x and the number of hours the Davis family used their sprinkler for is y.

So combined:

x + y = 45 hours

and we are also told that:

40x + 15y = 1300 L

So we can do simultaneous equations to solve the problem.

With some rearranging, we can figure out that:

y= 45 - x

and by substituting that into the second equation:

40x + 15 (45 -x) = 40x + 675 - 15x = 1300L

25x = 1300 - 675

25x = 625

x = 25 = hours that the Carter family used their sprinkler

and we can substitute that back into the original equation to find how many hours the Davis family used their sprinkler so:

25 + y = 56

y = 31

The Davis family used their sprinkler for 31 hours whilst the Carter family used their sprinkler for 25 hours.

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Delicious77 [7]

Answer:

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Step-by-step explanation:

The given trigonometric equation is $\cos(-\theta)=\frac{\sqrt{3} }{3}$ .

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According to the Pythagorean identity,

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We substitute this value in to the above Pythagorean identity to get;

$(\frac{\sqrt{3}}{3})^2+\sin^2\theta=1$

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$\Rightarrow \sin^2\theta=1-\frac{3}{9}$

$\Rightarrow \sin^2\theta=\frac{6}{9}$

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$\Rightarrow \sin\theta=\pm \frac{\sqrt{6}}{3}$

But we were given that,

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The correct answer is B

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4 years ago

Please help me I need to submit this asap

frez [133]

Answer:

Step-by-step explanation:

The average rate of change of f(x) in the closed interval [ a, b ] is

$\frac{f(b)-f(a)}{b-a}$

Here { a, b ] = [ - 1, 2 ], thus

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f(a) = $\frac{1}{2}$ ← from (- 1, $\frac{1}{2}$ ) , thus

average rate of change = $\frac{4-\frac{1}{2} }{2-(-1)}$ = $\frac{\frac{7}{2} }{3}$ = $\frac{7}{6}$ → D

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