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3 years ago

how many 4 letter words can you make from a list of 12 letters, if you use each letter only once in each word?

Mathematics

1 answer:

fiasKO [112]3 years ago

7 0

Answer:

it would be 3 because if you list words then just divide 12 by 4 and you get 3

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As a town gets smaller, the population of its high school decreases by 8% each year. The senior class has 320 students now. In h

Semmy [17]

Answer:

in 13.95 years the senior class will have 100 students.

Step-by-step explanation:

P(h) = p(0.92)^t (equation for exponential change)

P(h) - population of highschool (or senior class) = 100

p - staring amount = 320

t = time in years

100 = 320(0.92)^t

1/3.2 = .92^t (divide both sides by 320)

log(1/3.2, .92) = t (log base 0.92 of 1/3.2 equals t)

13.9497 = t

6 0

3 years ago

A rock thrown vertically upward from the surface of the moon at a velocity of 36m/sec reaches a height of s = 36t - 0.8 t^2 met

Verdich [7]

Answer:

a. The rock's velocity is $v(t)=36-1.6t \:{(m/s)}$ and the acceleration is $a(t)=-1.6 \:{(m/s^2)}$

b. It takes 22.5 seconds to reach the highest point.

c. The rock goes up to 405 m.

d. It reach half its maximum height when time is 6.59 s or 38.41 s.

e. The rock is aloft for 45 seconds.

Step-by-step explanation:

Velocity is defined as the rate of change of position or the rate of displacement. $v(t)=\frac{ds}{dt}$
Acceleration is defined as the rate of change of velocity. $a(t)=\frac{dv}{dt}$

The rock's velocity is the derivative of the height function $s(t) = 36t - 0.8 t^2$

$v(t)=\frac{d}{dt}(36t - 0.8 t^2) \\\\\mathrm{Apply\:the\:Sum/Difference\:Rule}:\quad \left(f\pm g\right)'=f\:'\pm g'\\\\v(t)=\frac{d}{dt}\left(36t\right)-\frac{d}{dt}\left(0.8t^2\right)\\\\v(t)=36-1.6t$

The rock's acceleration is the derivative of the velocity function $v(t)=36-1.6t$

$a(t)=\frac{d}{dt}(36-1.6t)\\\\a(t)=-1.6$

b. The rock will reach its highest point when the velocity becomes zero.

$v(t)=36-1.6t=0\\36\cdot \:10-1.6t\cdot \:10=0\cdot \:10\\360-16t=0\\360-16t-360=0-360\\-16t=-360\\t=\frac{45}{2}=22.5$

It takes 22.5 seconds to reach the highest point.

c. The rock reach its highest point when t = 22.5 s

Thus

$s(22.5) = 36(22.5) - 0.8 (22.5)^2\\s(22.5) =405$

So the rock goes up to 405 m.

d. The maximum height is 405 m. So the half of its maximum height = $\frac{405}{2} =202.5 \:m$

To find the time it reach half its maximum height, we need to solve

$36t - 0.8 t^2=202.5\\36t\cdot \:10-0.8t^2\cdot \:10=202.5\cdot \:10\\360t-8t^2=2025\\360t-8t^2-2025=2025-2025\\-8t^2+360t-2025=0$

For a quadratic equation of the form $ax^2+bx+c=0$ the solutions are

$x_{1,\:2}=\frac{-b\pm \sqrt{b^2-4ac}}{2a}$

$\mathrm{For\:}\quad a=-8,\:b=360,\:c=-2025:\\\\t=\frac{-360+\sqrt{360^2-4\left(-8\right)\left(-2025\right)}}{2\left(-8\right)}=\frac{45\left(2-\sqrt{2}\right)}{4}\approx 6.59\\\\t=\frac{-360-\sqrt{360^2-4\left(-8\right)\left(-2025\right)}}{2\left(-8\right)}=\frac{45\left(2+\sqrt{2}\right)}{4}\approx 38.41$

It reach half its maximum height when time is 6.59 s or 38.41 s.

e. It is aloft until s(t) = 0 again

$36t - 0.8 t^2=0\\\\\mathrm{Factor\:}36t-0.8t^2\rightarrow -t\left(0.8t-36\right)\\\\\mathrm{The\:solutions\:to\:the\:quadratic\:equation\:are:}\\\\t=0,\:t=45$

The rock is aloft for 45 seconds.

5 0

4 years ago

What are the solutions of this equation? x^ - x - 56 = 0

NikAS [45]

Answer:

y = 0

Step-by-step explanation:

8 0

3 years ago

Read 2 more answers

I need helpppppppppppp

____ [38]

you start at the origin and go down 4 right 1. So the range is 4 and the domain is x

Step-by-step explanation:

8 0

3 years ago

Read 2 more answers

Write the quadratic equation in general form and then choose the value of "b."

eduard

The answer is b. 11.

You can find this by multiplying the two parenthesis together. In order to do this, you can use a multiplying process known as FOIL (First, Outer, Inner, Last), where you multiply parts of the parenthesis in this order to make sure you do so properly.

First Numbers:
2x * x = 2x^2

Outer Numbers:
2x * 6 = 12x

Inner Numbers:
-1 * x = -1x

Last Numbers:
-1*6 = -6

Now place them all in that order and simplify.
2x^2 + 12x - x - 6 ---> simplify x terms
2x^2 + 11x - 6

Since the middle term (the one with the x value) has a coefficient of 11, that gives us a b value of 11.

3 0

3 years ago

how many 4 letter words can you make from a list of 12 letters, if you use each letter only once in each word?​

how many 4 letter words can you make from a list of 12 letters, if you use each letter only once in each word?