Help me find n<br><br> 4/5n=9/10

15. Suppose a box of 30 light bulbs contains 4 defective ones. If 5 bulbs are to be removed out of the box.

Naddika [18.5K]

Answer:

1) Probability that all five are good = 0.46

2) P(at most 2 defective) = 0.99

3) Pr(at least 1 defective) = 0.54

Step-by-step explanation:

The total number of bulbs = 30

Number of defective bulbs = 4

Number of good bulbs = 30 - 4 = 26

Number of ways of selecting 5 bulbs from 30 bulbs = $30C5 = \frac{30 !}{(30-5)!5!} \\$

$30C5 = 142506$ ways

Number of ways of selecting 5 good bulbs from 26 bulbs = $26C5 = \frac{26 !}{(26-5)!5!} \\$

$26C5 = 65780$ ways

Probability that all five are good = 65780/142506

Probability that all five are good = 0.46

2) probability that at most two bulbs are defective = Pr(no defective) + Pr(1 defective) + Pr(2 defective)

Pr(no defective) has been calculated above = 0.46

Pr(1 defective) = $\frac{26C4 * 4C1}{30C5}$

Pr(1 defective) = (14950*4)/142506

Pr(1 defective) =0.42

Pr(2 defective) = $\frac{26C3 * 4C2}{30C5}$

Pr(2 defective) = (2600 *6)/142506

Pr(2 defective) = 0.11

P(at most 2 defective) = 0.46 + 0.42 + 0.11

P(at most 2 defective) = 0.99

3) Probability that at least one bulb is defective = Pr(1 defective) + Pr(2 defective) + Pr(3 defective) + Pr(4 defective)

Pr(1 defective) =0.42

Pr(2 defective) = 0.11

Pr(3 defective) = $\frac{26C2 * 4C3}{30C5}$

Pr(3 defective) = 0.009

Pr(4 defective) = $\frac{26C1 * 4C4}{30C5}$

Pr(4 defective) = 0.00018

Pr(at least 1 defective) = 0.42 + 0.11 + 0.009 + 0.00018

Pr(at least 1 defective) = 0.54

3 0

3 years ago

A sector of a circle has a central angle of 45 . Find the area of the sector if the radius of the circle is 15 cm.

prohojiy [21]

Answer:

A = 28.125 * pi cm^2

A = 88.357 cm^2

Step-by-step explanation:

Area of a sector is 1/2 r^2 theta where theta is in radians

convert 45 degrees to radians

theta = 45 * pi/180 = pi/4

A = 1/2 * 15^2 * pi/4

A =1/2 * 225 * pi/4

A = 28.125 * pi cm^2

A = 88.357 cm^2

6 0

2 years ago

Which is a needed step to prove that AABF = AEDG?

Gwar [14]

Answer: helllloooooooooooooo000000oooo

Step-by-step explanation:

7 0

2 years ago

If a wheel with a radius of 80 inches spins at a rate of 50 revolutions per minute, find the approximate linear velocity in mile

Lubov Fominskaja [6]

$\bf \textit{arc's length}\\\\
s=rw\qquad 
\begin{cases}
r=radius\\
w=\textit{angular speed}
\end{cases}\qquad w=\cfrac{50 rev}{min}\cdot \cfrac{2\pi }{rev}
\\\\\\
w=\cfrac{100\pi }{min}\qquad s=80in\cdot \cfrac{100\pi }{min}\implies s=\cfrac{8000\pi\ in}{min}\\\\
-------------------------------\\\\
\textit{now to convert it to miles/hr}
\\\\\\
\cfrac{8000\pi\ in}{min}\cdot \cfrac{ft}{12in}\cdot \cfrac{mile}{5280ft}\cdot \cfrac{60min}{hr}\implies \cfrac{8000\pi \cdot 60\ in}{12\cdot 5280\ hr}$

3 0

3 years ago

Jocelyn owns a food truck that sells tacos and burritos. She only has enough supplies to make 150 tacos or burritos. She sells e

timurjin [86]

Answer:

We know that:

Price of a taco = $4

Price of a burrito = $6.50

x = number of tacos sold

y = number of burritos sold.

We must have that:

x + y ≤ 150 (Because she only has supplies to make 150 tacos or burritos, but she can sell less than that)

And also we know that she must sell at least $780, then:

x*$4 + y*$6.50 ≥ $780

Now we found the system of inequalities:

x + y ≤ 150

x*$4 + y*$6.50 ≥ $780

To solve it graphically, we just need to find each one of the region solutions for each equation, and the intersection of these regions will be the solution for the system.

To graph them may be easier to write them as lines, you can do it as follows:

y ≤ 150 - x

y ≥ ($780 - x*$4)/$6.50

in the first equation, we will shade the area below the line, and in the second equation, we will shade the area above the line.

You can see the image below.

Where the accepted solutions are the ones in the darker part, and we only restrict this to positive values of x (because of how we defined the variable x)

Then looking at the image, we can see that one solution can be the point

x = 20, y = 120

7 0

3 years ago

Help me find n 4/5n=9/10