answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Elodia [21]
2 years ago
5

In a batch of 100 cell phones, there are, on average, 5 defective ones. if a random sample of 30 is selected, find the probabili

ty of having 2 defective phones.
Mathematics
1 answer:
Dafna11 [192]2 years ago
5 0

Let x be the number of defective cell phones. It is given that in batch of 100, on average 5 are defective.

let p be the probability of defective cell phone.

p = 5/100 = 0.05

Let n be size of random sample, n=30

Here out of 30 we want to find probability that 2 will be defective. It means 30-2 =28 cell phones will be non defective.

The probability of getting non defective cell phone is 1- p=1-0.05 =0.95

The probabability of getting 2 defective is

P(X=2) = number of ways selecting 2 from 30 * probability 2 defective * probability of 28 non defective

Now number of ways of selecting 2 cell phone from 30 is

30C2 = \frac{30!}{(30-2)! 2!}

= \frac{30!}{28! 2!}

= \frac{30 *29* 28!}{28! 2!}

= (30*29) /2

30C2 = 435

P(X=2) = 30C2 * (0.05)^2 * (0.95)^28

= 435 * 0.0025 * 0.2378

P(X=2) = 0.2586

Probability of getting 2 defective out of 30 is 0.2586

You might be interested in
713.49 written in a standard form
Vikki [24]

Answer: one hundred  seven thirteen and forty-nine hundreds

Step-by-step explanation: Standard form is a way of writing down very large or very small numbers easily. 103 = 1000, so 4 × 103 = 4000 . So 4000 can be written as 4 × 10³ . This idea can be used to write even larger numbers down easily in standard form.

7 0
2 years ago
Show that b^2 is greater than equal to or less than ac, according as a, b, c are in A.P., G.P.
ValentinkaMS [17]

Answer/Step-by-step explanation  (ac > b² or b² < ac. )

A/c to question, we have to show:-

b² >ac in A.P ........ (1)

b² = ac in G.P .....(2)

b² < ac in H.P. ..... (3)

b = a+c/2 (A.P)

b = √ac ( G.P)

b = 2ac/a+c (H.P)

In A.P :

b² > ac = b² - ac

= (a+c/2)² - ac

= (a²+2ac+c²/4) - ac  = a² + 2ac + c² - 4ac / 4

= a² - 2ac + c² / 4  = ( a - c ) ² / 4 > 0  Hence, b²>ac

In G.P:-

b = √ac

Hence, b² = ac

In H.P :-  b² < ac = ac > b²  = ac - b²  = ac - ( 2ac / a+c)

= ac(a+c) - 2ac / a+c

= a²c + ac² - 2ac / a+c

= ac(2ac - 2) / a+c > 0

Hence, ac > b² or b² < ac.

5 0
1 year ago
PLEASE HELP ME  Which of the following is the correct graph of the compound inequality 4p + 1 &gt; −7 or 6p + 3 &lt; 33? (1 poin
nikitadnepr [17]
The first inequality has solution
  4p > -8 . . . . . . subtract 1
  p > -2 . . . . . . . divide by 4
This is graphed as an open dot at -2, with shading to the right.

Neither inequality symbol includes "or equal to", so both dots are open dots. The appropriate choice is the first one:
  a number line with open circles at negative 2 and 5 with shading in between
4 0
2 years ago
Read 2 more answers
You and a friend buy two fruit smoothies and leave a tip. You split the total and your half comes to $3.60. What percent tip (in
Bezzdna [24]

the amount they paid includes the price of the two smoothies and tip

since the friends are splitting the bill in 2, then each friend pays only half the amount

each friend pays $ 3.60 each

so the total amount they both paid is 3.60 x 2 = $ 7.20

the cost of one smoothie - $3

therefore the cost of the 2 smoothies - 3 x 2 = $ 6

so they paid 7.20 but the bill was only 6 dollars

so the difference in the 2 amounts is the value of the tip they left

tip = 7.20 - 6 = 1.20

so the percentage of the tip is - tip amount / value of the bill x 100 %

percentage = 1.20 / 6.0 x 100 % = 20 %

they left 20 % of the bill as a tip

6 0
2 years ago
Read 2 more answers
Triangle XYZ is translated by the rule (x + 1, y â 1) and then dilated by a scale factor of 4 centered at the origin. Which stat
marysya [2.9K]

Answer:  Y and Y'' are congruent after the translation, but not after the dilation.

Step-by-step explanation:

We know that we generally prefer rigid transformations if want to create congruent images.

There are three basic kinds of rigid transformations:  

1) rotation 2) reflection 3) translation

So, they all create congruent images.

But a dilation does not create congruent images because it creates an image of similar same shape as the original but not the same size.

Given : Triangle XYZ is translated and then dilated by a scale factor of 4 centered at the origin.

Then, the correct option is "Y and Y'' are congruent after the translation, but not after the dilation."

5 0
2 years ago
Other questions:
  • Which of the following represents the measures of all angles coterminal with a 418° angle?
    15·2 answers
  • Which linear inequality is represented by the graph?
    12·2 answers
  • The probability that Edward purchases a video game from a store is 0.67 (event A), and the probability that Greg purchases a vid
    8·2 answers
  • The results of an election are shown in the table below.
    12·1 answer
  • Irene owns a bakery.For each cake,she spends 1/4 of an hour to make frosting and 2/5 hour to decorate.How many cakes can Irene b
    5·1 answer
  • Sasha says that she drew an acute isosceles triangle with side lengths of 6 cm, 9 cm, and 12 cm and angles of 30°, 50°, and 100°
    8·1 answer
  • Five hundred sixth-grade students
    6·1 answer
  • A referee moves along a straight path on the side of an athletic field. The velocity of the referee is given by v(t) = 4(1-6)cos
    10·1 answer
  • Which point on the number line represents the product (5)(-2)(-1)2
    14·2 answers
  • Matrix is handing out treats at a local protest to promote his new detective agency. He allows each participant to reach into hi
    5·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!