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3 years ago

After how many audio books will both book clubs cost the same amount.

Mathematics

1 answer:

bulgar [2K]3 years ago

4 0

Answer:

2 books

Step-by-step explanation:

10 + 5x = 16 + 2x

- 2x - 2x

10 + 3x = 16

-10 -10

3x = 6

/3 /3

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If the median of the score distribution on this pop quiz is more than 170, the teacher will drop the next pop quiz. The pop quiz

antiseptic1488 [7]

Answer:

174.50

Step-by-step explanation:

first order the numbers from least to greatest then find the middle digit. if there are two, add them together, then divide them by 2. if there's only one, that is your median.

8 0

3 years ago

The surface area of a melting snowball decreases at a rate of3.8cm2/min. Find the rate at which its diameter decreases when the

Scorpion4ik [409]

Answer:

Step-by-step explanation:

This is a pretty basic related rates problem. I'm going to go through this just like I do in class when I'm teaching it to my students.

We see we have a snowball, which is a sphere. We are talking about the surface area of this sphere which has a formula of

$S=4\pi r^2$

In the problem we are given diameter, not radius. What we know about the relationship between a radius and a diameter is that

d = 2r so

$\frac{d}{2}=r$ Now we can have the equation in terms of diameter instead of radius. Rewriting:

$S=4\pi(\frac{d}{2})^2$ which simplifies to

$S=4\pi(\frac{d^2}{4})$ and a bit more to

$S=\pi d^2$ (the 4's cancel out by division). Now that is a simple equation for which we have to find the derivative with respect to time.

$\frac{dS}{dt}=\pi*2d\frac{dD}{dt}$ Now let's look at the problem and see what we are given as far as information.

The rate at which the surface area changes is -3.8, and we are looking for $\frac{dD}{dt}$ , the rate at which the diameter is changing, when the diameter is 13. Filling in:

$-3.8=\pi(2)(13)\frac{dD}{dt}$ and solving for the rate at which the diameter is changing:

$-\frac{3.8}{26\pi}=\frac{dD}{dt}$ and divide to get

$\frac{dD}{dt}=-.459\frac{cm}{min}$ Obviously, the negative means that the diameter is decreasing.

7 0

3 years ago

Convert this number given in standard form into scientific notation. 0. 0000069 What is the value in scientific notation? 0. 69

Len [333]

Scientific notation is used so that the order of the number is known in first glance. The value of the given number in scientific notation is given by: Option B: $6.9 \times 10^{-6}$

<h3>How does scientific notations work?</h3>

The number is written in the form $a \times 10^b$ where we have $1 \leq a < 10$

The number b shows the order, which is the most important figure for which scientific notation is used. It tells us how much order large or small a value is in powers of 10. We can for a time, ignore the value of 'a' for two comparable quantities and only compare their orders(this type of comparison is useful when difference is too big, like size of human to size of a star etc sort of comparisons).

Scientific notations have some of the profits as:

Better readability due to compact representation
Its value in terms of power of 10 is known, which helps in easy comparison of quantities differing by a large value.

For the given case, the number in consideration is 0.0000069

Rewriting it in fraction form, we get:

$0.0000069 = \dfrac{69}{10000000} = \dfrac{69}{10^7} = 69 \times 10^{-7} = 6.9 \times 10 \times 10^{-7}\\\\0.0000069 = 6.9 \time 10 ^{-7 +1} \\0.0000069 = 6.9\times 10^{-6}$