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3 years ago

10

A lock has a code of 4 numbers between 1 and 20. If no numbers in the

1 answer:

son4ous [18]3 years ago

4 0

20x19x18x17 = 116,280

You might be interested in

Given cos(x)=1/2, what is the value of cos(x+pi)?

patriot [66]

Answer:

-1/2

Step-by-step explanation:

cos(x+pi) = -cos(x), so the answer is -1/2.

8 0

2 years ago

What is the equation of the quadratic graph with a focus of (1, 1) and a directrix of y = −1?

JulsSmile [24]

Alright,
directix is y=something so it opens down or up

we use
(x-h)²=4p(y-k)
the vertex is (h,k)
and p is distance from focus to vertex
if focus is above directix, p is positive
if focus is below directix, p is negative

so we gts

focus=(1,1)
directix is y=-1
1>-1
focus is above

oh, vertex is in middle of focus and directix
so
beteeen (1,1) and y=-1 is, hmm
that is a distance of 2 vertically
2/2=1
1 down from (1,1) is (1,0)
vertex is (1,0)
p=1

so
(x-1)²=4(1)(y-0)
solving for y to get into f(x)=something form
(x-1)²=4y
y=1/4(x-1)²
f(x)=1/4(x-1)²

4th option

6 0

2 years ago

A study claims that college students spend an average of 4 hours or less studying per day. A researcher wants to check if this c

kirill115 [55]

<h2>Answer with explanation:</h2>

Let $\mu$ be the population mean.

By observing the given information, we have :-

$H_0:\mu\leq4\\\\H_a:\mu>4$

Since the alternative hypotheses is left tailed so the test is a right-tailed test.

We assume that the time spend by students per day is normally distributed.

Given : Sample size : n=121 , since n>30 so we use z-test.

Sample mean : $\overline{x}=3.15$

Standard deviation : $\sigma=1.2$

Test statistic for population mean :-

$z=\dfrac{\overline{x}-\mu}{\dfrac{\sigma}{\sqrt{n}}}$

$\Rightarrow\ z=\dfrac{3.15-4}{\dfrac{1.2}{\sqrt{121}}}\\\\\Rightarrow\ z=-7.79166666667\approx-7.79$

Critical value (one-tailed) corresponds to the given significance level :-

$z_{\alpha}=z_{0.1}=1.2816$

Since the observed value of z (-7.79) is less than the critical value (1.2816) , so we do not reject the null hypothesis.

Hence, we conclude that we have enough evidence to accept that the college students spend an average of 4 hours or less studying per day.

4 0

2 years ago

Can y'all help me with my math problem please

Greeley [361]

Answer:

it is C

Step-by-step explanation:

3 0

2 years ago

Read 2 more answers

Graph the linear inequality: 2x + 3y = 12, by creating a t-chart to plot the points. Shade by

Crazy boy [7]

Answer:

See explanation

Step-by-step explanation:

Assuming the given inequality is $2x+3y\le12$

Then the corresponding linear equation is $2x+3y=12$

When x=0, we have $2*0+3y=12$

$\implies 3y=12\implies y=4$

When y=0, we have $2x+3*0=12$

$\implies 2x=12\implies x=6$

The T-table is:

<u>x | y</u>

0 | 4

6 | 12

We plot this points and draw a solid straight line as shown in the attachment.

Now let us test the origin: (0,0) by plugging x=0 and y=0 into the inequality.

$2*0+3*0\le12$

$0\le12$ ....This is true so we shade the lower half plane as shown in the attachment.

6 0

2 years ago