If 5 + 20 times 2^2 minus 3x = 10 times 2^- 2x + 5, what is the value of x?

. A survey of 30 students is taken. 11 students say that mathematics is their favorite subject. Based on this survey, how many s

Sveta_85 [38]

Ok, so based on a survey - you know that out of 30 students, 11 said that their favourite subject is mathematics. :-)

This means that:

11/30 of these students think mathematics if their favourite subject.

Now, in order to answer your question, we are going to have to change the denominator of the fraction above to 1000. Whatever we do to the denominator of this fraction, we must do to the numerator of this fraction.

Example:

$\frac { 11 }{ 30 } \times \frac { \frac { 1000 }{ 30 } }{ \frac { 1000 }{ 30 } } \\ \\ =\frac { \frac { 11000 }{ 30 } }{ 1000 } \\ \\ =\frac { 366.\dot { 6 } }{ 1000 }$

This means that rounded to the nearest ten, theoretically speaking, 370 students out of 1000 would say that mathematics is their favourite subject.

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3 years ago

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Arnold is trying to make packing boxes out of 6 foot by 6 foot pieces of cardboard from the local grocer. Help Arnold decide how

lions [1.4K]

<span>Part I: Determining Dimensions

Arnold has been given a 6 foot by 6 foot sheet of cardboard to make an open box by cutting an equal size square from each corner, folding up the resulting flaps, and taping at the corners. Your task is to label dimensions on a sketch with the same size variable cut from each corner.

*You don't have to draw one, just explain what it would look like*

Answer:

Base of the box:

     it is a square
     side of the base = 6 foot - x - x. = 6 - 2x

Height of the box: x

Part II: Analyze

How does each variable expression relate to the length, width, and height of the box when folded?

Answer:

length = width = 6 - 2x
height = x

Part III: Extend your Findings
a. Based upon the variables you used in Part II, write a product for the volume.

Answer:

Volume = area of the base × height

Volume = (6 - 2x)² x

b. Expand the product to write a volume function.

Answer:

Volume = (36 - 24x + 4x²)x

Volume = 36x - 24x² + 4x³

c. What domain makes sense for the volume?

Answer:

Since x is a physical dimension x is greater than 0

Since the lenght of the cardboarc sheet is 6 and two squares are cut off, x has to be less than 3

So, the domain is (0, 3)

d. Guess and check values to find the size cut that produces a maximum volume.
*Six guesses are required*

Answer:

x              </span>Volume = 36x - 24x² + 4x³

0.1           36(0.1) - 24(0.1)² + 4(0.1)³ = 3.36
0.5           36(0.5) - 24(0.5)² + 4(0.5)³ = 12.5
1.0           36 - 24 + 4 = 16
1.5           36(1.5) - 24(1.5)² + 4(1.5)³ = 13.5
2.0           36(2) - 24(2)² + 4(2)³ = 8
1.7           36(1.7) - 24(1.7)² + 4 (1.7)³ = 11.49
1.2           36(1.2) - 24(1.2)² + 4(1.2)³ = 15.55

Then you can guess that the maximum volume is pretty close to 16 and it is whenx is close to 1.
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