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3 years ago

Can you please answer ASAP I need the answer

Mathematics

1 answer:

Alika [10]3 years ago

7 0

Answer:

I think x=8

Step-by-step explanation:

5(x+7)+15=90

90 because it's a 90 degree angle

5x+35+15=90

5x+50=90

5x=40

x=8

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Please help me! Only have about 10 minutes until I have to submit this assignment!

salantis [7]

Answer:

626

Step-by-step explanation

8 0

3 years ago

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Reena bought a mobile phone for 16,240 that included a GST of 12%. Find the price of the mobile phone before the GST was added.

NNADVOKAT [17]

Answer: 14500

Step-by-step explanation:

Let the price of the mobile phone before the GST was added be represented by x.

Therefore,

x + (12% × x) = 16240

x + 0.12x = 16240

1.12x = 16240

x = 16240/1.12

x = 14500

The price of the mobile phone before the GST was added was 14500

4 0

3 years ago

You are a lifeguard and spot a drowning child 60 meters along the shore and 40 meters from the shore to the child. You run along

sukhopar [10]

Answer:

The lifeguard should run across the shore a distance of 48.074 m before jumpng into the water in order to minimize the time to reach the child.

Step-by-step explanation:

This is a problem of optimization.

We have to minimize the time it takes for the lifeguard to reach the child.

The time can be calculated by dividing the distance by the speed for each section.

The distance in the shore and in the water depends on when the lifeguard gets in the water. We use the variable x to model this, as seen in the picture attached.

Then, the distance in the shore is d_b=x and the distance swimming can be calculated using the Pithagorean theorem:

$d_s^2=(60-x)^2+40^2=60^2-120x+x^2+40^2=x^2-120x+5200\\\\d_s=\sqrt{x^2-120x+5200}$

Then, the time (speed divided by distance) is:

$t=d_b/v_b+d_s/v_s\\\\t=x/4+\sqrt{x^2-120x+5200}/1.1$

To optimize this function we have to derive and equal to zero:

$\dfrac{dt}{dx}=\dfrac{1}{4}+\dfrac{1}{1.1}(\dfrac{1}{2})\dfrac{2x-120}{\sqrt{x^2-120x+5200}} \\\\\\\dfrac{dt}{dx}=\dfrac{1}{4} +\dfrac{1}{1.1} \dfrac{x-60}{\sqrt{x^2-120x+5200}} =0\\\\\\ \dfrac{x-60}{\sqrt{x^2-120x+5200}} =\dfrac{1.1}{4}=\dfrac{2}{7}\\\\\\ x-60=\dfrac{2}{7}\sqrt{x^2-120x+5200}\\\\\\(x-60)^2=\dfrac{2^2}{7^2}(x^2-120x+5200)\\\\\\(x-60)^2=\dfrac{4}{49}[(x-60)^2+40^2]\\\\\\(1-4/49)(x-60)^2=4*40^2/49=6400/49\\\\(45/49)(x-60)^2=6400/49\\\\45(x-60)^2=6400\\\\$

$x$

As $d_b=x$ , the lifeguard should run across the shore a distance of 48.074 m before jumpng into the water in order to minimize the time to reach the child.

7 0

4 years ago

Hey hey hey. help pls

Firdavs [7]

Answer:

Emma spend 8 hours in homework in a week and Jared spends 16 hours in homework in 2 weeks.

Step-by-step explanation:

Two quantities P and Q are said to be in PROPORTION if and only if for all values of P and q, we get:

$\frac{P}{Q} = k$

Here, k : PROPORTIONALITY CONSTANT

Case: 1

5 hour piano practice in 1 week.

So, the piano practice in 2 weeks( 1 x 2) = 2 x 5 = 10 hours

But here, it is given to be 12 hours in 2 weeks.

Hence, NOT PROPORTIONAL.

Case 2:

70 words in 60 seconds.

So, the words typed in 210 seconds ( 60 x 3.5) = 70 x 3.5 = 240 words

But here, it is given to be 280 words in 210 seconds.

Hence, NOT PROPORTIONAL.

Case: 3

8 hour homework in 1 week.

So, the homework done in 2 weeks( 1 x 2) = 2 x 8 = 16 hours

It is given to be 16 hours in 2 weeks.

Hence, PROPORTIONAL.

Case: 4

15 miles in 78 minutes.

So, the distance covered in 102 minutes (78 x 1.3) = 15 x 1.3 = 19.6 miles

But here, it is given to be 17 miles in 102 minutes.

Hence, NOT PROPORTIONAL.

Case: 5

18 miles in 45 minutes.

So, the distance covered in 55 minutes (45 x 1.2) = 18 x 1.2 = 21.6 miles

But here, it is given to be 22 miles in 55 minutes.

Hence, NOT PROPORTIONAL.

Hence, the only proportional case is Emma spend 8 hours in homework in a week and Jared spends 16 hours in homework in 2 weeks.

6 0

3 years ago

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Length of two sides of a triangle is given as 4cm and 4cm which triangle is this

My name is Ann [436]

Answer:

isosceles triangle

Step-by-step explanation:

two equal sides. is this the question only?

6 0

3 years ago

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