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2 years ago

Tim must choose 4 graphic novels out of a collection of 13 to take on vacation.

Mathematics

2 answers:

Vsevolod [243]2 years ago

7 0

$C(13,4)=\dfrac{13!}{4!9!}=\dfrac{10\cdot11\cdot12\cdot13}{2\cdot3\cdot4}=715$

Kay [80]2 years ago

7 0

there are 715 ways to choose (C, 715)

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PLEASE HELP!!!!!!!!! Ernest's friend rolls a six-sided number cube and lands on square 8. She asks Ernest to guess what number s

hjlf

Answer:

he reads

Step-by-step explanation:

7 0

1 year ago

An example problem in a Statistics textbook asked to find the probability of dying when making a skydiving jump.

MArishka [77]

Answer:

(a) 0.999664

(b) 15052

Step-by-step explanation:

From the given data of recent years, there were about 3,000,000 skydiving jumps and 21 of them resulted in deaths.

So, the probability of death is $\frac{21}{3000000}==0.000007$ .

Assuming, this probability holds true for each skydiving and does not change in the present time.

So, as every skydiving is an independent event having a fixed probability of dying and there are only two possibilities, the diver will either die or survive, so, all skydiving can be regarded as is Bernoulli's trial.

Denoting the probability of dying in a single jump by $q$ .

$q=7\times 10^{-6}=0.000007$ .

So, the probability of survive, $p=1-q$

$\Rightarrow p=1-7\times 10^{-6}=0.999993.$

(a) The total number of jump he made, n=48

Using Bernoulli's equation, the probability of surviving in exactly 48 jumps (r=48) out of 48 jumps (n=48) is

$=\binom(n,r)p^rq^{n-r}$

$=\binom(48,48)(0.999993)^{48}(0.000007)^{48-48}$

$=(0.999993)^{48}=0.999664$ (approx)

So, the probability of survive in 48 skydiving is 0.999664,

(b) The given probability of surviving =90%=0.9

Let, total $n$ skydiving jumps required to meet the surviving probability of 0.9.

So, By using Bernoulli's equation,

$0.9=\binom {n }{r} p^rq^{n-r}$

Here, r=n.

$\Rightarrow 0.9=\binom{n}{n}p^nq^{n-n}$

$\Rightarrow 0.9=p^n$

$\Rightarrow 0.9=(0.999993)^n$

$\Rightarrow \ln(0.9)=n\ln(0.999993)$ [ taking $\log_e$ both sides]

$\Rightarrow n=\frac {\ln(0.9)}{\ln(0.999993)}$

$\Rightarrow n=15051.45$

The number of diving cant be a fractional value, so bound it to the upper integral value.

Hence, the total number of skydiving required to meet the 90% probability of surviving is 15052.

3 0

2 years ago

Abdullah is a quality control expert at a factory that paints car parts. He knows that 20\ , percent of parts have an error in t

-Dominant- [34]

The error rate has decreased after changing the painting process.

<u>Step-by-step explanation:</u>

Abdulla knows that 20 percent of the parts have an error in their painting. After suggesting changes in painting process, he wants to know whether the error rate has changed.

Number of parts in the random sample=400400400

Number of parts that had an error=606060

We have to determine what percentage of 400400400 is 606060

$606060=x/100 \times 400400400\\=0.15%$

After changing the painting process 0.15% of parts have error.

The previous percentage was 20.Hence the error rate has clearly changed.

3 0

1 year ago

If one serving is 1/6 of a tray of lasagna, how many servings are in three trays of lasagna?

lbvjy [14]

Answer:

18 servings

Step-by-step explanation:

$\dfrac{3}{(\frac{1}{6})}= \\\\3\times \left(\frac{6}{1}\right)= \\\\3\times 6= \\\\18$

Hope this helps!

4 0

2 years ago

which equation is in slope-intercept form and represents a line with slope 3 through the point (9,-4)

krek1111 [17]

Slope-intercept form is y = mx +b, where the variable m represents the slope of the line and the variable b represents the y-intercept of the line. Since we weren't given the y-intercept, one way to solve this problem is substitute the slope for the variable m and then the x and y values from the ordered pair to solve for b.

y = mx + b

y = 3x + b

-4 = 3(9) + b

Now, we can simplify by computing the multiplication on the right side of the equation.

-4 = 27 + b

Finally, we can find the value for b by subtracting 27 from both sides of the equation to get:

-31 = b

Now, we should substitute this value for b back into our equation with the slope.

y = 3x - 31

Therefore, your answer is y = 3x - 31.

Hope this helps!

6 0

2 years ago

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