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3 years ago

If Sarah has 30 bills in her wallet worth $240, all fives and tens, how many of each bill does she have? help

Mathematics

1 answer:

Ivenika [448]3 years ago

5 0

Answer:

12 fives and 18 tens

Step-by-step explanation:

solving this we need 2 different equations

one for he total bills and one for the total money

x+y=30

that is total bills

5x+10y=240

combining both equations we can use elimination method and get

12 five dollar bills and 18 ten dollar bills

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2 years ago

What is the average rate of change of f(x) = -x2 + 3x + 6 over the interval –3

Rufina [12.5K]

Answer:

$\frac{\Delta y}{\Delta x} =\frac{f(x_2)-f(x_1)}{x_2-x_1} =\frac{6-(-12)}{3-(-3)} =\frac{18}{6}= 3$

Step-by-step explanation:

To find the average rate of change of a function over a given interval, basically you need to find the slope. The mathematical definition of the slope is very similar to the one we use every day. In mathematics, the slope is the relationship between the vertical and horizontal changes between two points on a surface or a line. In this sense, the slope can be found using the following expression:

$Average\hspace{3}rate\hspace{3}of\hspace{3}change=Slope=\frac{y_2-y_1}{x_2-x_1} =\frac{f(x_2)-f(x_1)}{x_2-x_1}$

So, the average rate of change of:

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Over the interval $-3$

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$f(x_2)=f(3)=-(3)^2+3(3)+6=-9+9+6=6\\\\f(x_1)=f(-3)=-(-3)^2+3(-3)+6=-9-9+6=-12$

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3 years ago

A truck with a heavy load drove from Boston to New York at 50 mph. After dropping of the load, it returned from New York to Bost

leva [86]

Answer:

175/3 or 58.333...

Step-by-step explanation:

This is fairly complicated but I will try to make it as simple as possible. I also apologize in advance for how impossible it is to make fractions look like fractions. I also had to insert a bunch of unnecessary parentheses just because the fractions that I can make are relatively inaccurate.

The distance between 2 cities can be represented as d.

Time is d/r if r is rate, so B->NY=d/50

Similarly,NY->B is d/70

Obviously the average speed is 2d/(d/50+d/70), this is just an average time

Now just remove the d and get (d/d)*2/(1/50+1/70)

You can now multiply by the LCM/LCM, which is 350/350.

After calculating you will get 700/12 which is 58.333...(This is how to enter into your RSM browser) Hope this helps. Sorry it is so late.

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tankabanditka [31]

Answer:

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Step-by-step explanation:

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