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2 years ago

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A man drove 210 miles in 3.5 hours. If the posted speed limit was 55 mph (miles per hour) the entire way, approximately how many

miles per hour over the speed limit was he going?

1 answer:

Alona [7]2 years ago

5 0

Answer:

5mph over the speed limit

Step-by-step explanation:

In 1 hour the man drove 210/3.5=60 miles. 60mph is over the speed limit (55) by 5 mph.

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2 years ago

What is -a^-2 if a=-5

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3 years ago

Solve the proportions:

IRINA_888 [86]

<u>Answer:</u>

6. 6.75
7. 27
8. 92/17
9. 49

<u>Step-by-step explanation:</u>

<u>- Question 6 -</u>

9/16 = x/12
=> 16x = 12 x 9
=> 16x = 108
=> x = 6.75

Hence, <u>the value of x in this proportion is 6.75.</u>

<h3>_______________________________</h3>

<u>- Question 7 -</u>

-3 + x/18 = 12/9
=> -3/18 + x/18 = 4/3
=> x/18 = 4/3 + 1/6
=> x/18 = 8/6 + 1/6
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=> x = 27

Hence, <u>the value of x is 27</u>

<h3>_______________________________</h3>

<u>- Question 8 -</u>

17/15 = 10/2x - 2

=> 17(2x - 2) = 150

=> 34x - 34 = 150

=> 34x = 184

=> x = 184/34

=> x = 92/17

Hence, <u>the value of x is 92/17</u>

<h3>_______________________________</h3>

<u>- Question 9 -</u>

x - 16/x + 6 = 3/5
=> 5(x - 16) = 3(x + 6)
=> 5x - 80 = 3x + 18
=> 2x = 98
=> x = 49

Hence, <u>the value of x is 49.</u>

<h3>_______________________________</h3>

Hoped this helped.

3 0

2 years ago

Is math related to science only answer if you know this

seropon [69]

Answer:

its sim iler

Step-by-step explanation:

7 0

3 years ago

Read 2 more answers

natima [27]

Answer:

See explanation

Step-by-step explanation:

Let x be the number of spade shovels, y -the number of flat shovels and z - the number of square showels sold that day.

The store keeps an inventory of 80 shovels, then

x+y+z=80

The store always buy twice as many spade shovels as square, so

x=2z

The total cost of all shovels is

16x+9.60y+12.80z=1,072

a) The system of three equations is

$\left\{\begin{array}{l}x+y+z=80\\ \\x=2z\\ \\16x+9.60y+12.80z=1,072\end{array}\right.$

b) In matrix form this is

$\left(\begin{array}{ccc}1&1&1\\ 1&0&-2\\ 16&9.60&12.80\end{array}\right)\cdot \left(\begin{array}{c}x\\y\\z\end{array}\right)=\left(\begin{array}{c}80\\0\\1,072\end{array}\right)$

c) The determinant is

$\left\|\begin{array}{ccc}1&1&1\\ 1&0&-2\\ 16&9.60&12.80\end{array}\right\|=0-32+9.60-0+19.20-12.80=-16$

d) Find three determinants:

$\left\|\begin{array}{ccc}80&1&1\\ 0&0&-2\\ 1,072&9.60&12.80\end{array}\right\|=0-2,144+0-0+1,536-0=-608$

$\left\|\begin{array}{ccc}1&80&1\\ 1&0&-2\\ 16&1,072&12.80\end{array}\right\|=0-2,560+1,072-0+2,144-1,024=-368$

$\left\|\begin{array}{ccc}1&1&80\\ 1&0&0\\ 16&9.60&1,072\end{array}\right\|=0+0+768-0-0-1,072=-304$

So,

$x=\dfrac{-608}{-16}=38\\ \\y=\dfrac{-368}{-16}=23\\ \\z=\dfrac{-304}{-16}=19$

e) If the store doubled all prices and inventory, then the new matrix is

$\left(\begin{array}{ccc}1&1&1\\ 1&0&-2\\ 32&19.20&25.60\end{array}\right)\cdot \left(\begin{array}{c}x\\y\\z\end{array}\right)=\left(\begin{array}{c}160\\0\\2,144\end{array}\right)$

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3 years ago