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4 years ago

8

Complete the table by providing justification for each step of the proof. Conjecture: If 4(x2 – 2) = 28, then x is 3 or –3

1 answer:

Anika [276]4 years ago

5 0

<span>4(x2 – 2) = 28
4x^2-8=28 Distributive law of multiplication

4x^2+8=28+8 Additive identity
4x^2=36 ; adding 8 to both sides
x^2 =9, dividing both sides by 4
x= +/- 3</span>

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Suppose approximately 75% of all marketing personnel are extroverts, whereas about 70% of all computer programmers are introvert

Setler [38]

Answer:

$P(x \ge 5) = 1.000$ ---- At least 5 from marketing departments are extroverts

$P(x=15) = 0.013$ ---- All from marketing departments are extroverts

$P(x = 0) = 0.002$ ---------- None from computer programmers are introverts

Step-by-step explanation:

See comment for complete question

The question is an illustration of binomial probability where

$P(x) = ^nC_x * p^x * (1 - p)^{n-x}$

$(a):\ P(x \ge 5)$

$n = 15$ --- marketing personnel

$p = 75\%$ --- proportion that are extroverts

Using the complement rule, we have:

$P(x \ge 5) = 1 - P(x < 5)$

So, we have:

$P(x < 5) =P(x = 0) + P(x = 1) + P(x = 2) + P(x = 3) + P(x = 4)$

$P(x = 0) = ^{15}C_{0} * (75\%)^0 * (1 - 75\%)^{15 - 0} = 1 * 1 * (0.25)^{15} = 9.31 * 10^{-10}$

$P(x = 1) = ^{15}C_{1} * (75\%)^1 * (1 - 75\%)^{15 - 1} = 15* (0.75)^1 * (0.25)^{14} = 4.19 * 10^{-8}$

$P(x = 2) = ^{15}C_{2} * (75\%)^2 * (1 - 75\%)^{15 - 2} = 105* (0.75)^2 * (0.25)^{13} = 8.80 * 10^{-7}$

$P(x = 3) = ^{15}C_{3} * (75\%)^3 * (1 - 75\%)^{15 - 3} = 455* (0.75)^2 * (0.25)^{12} = 0.0000153$

$P(x = 4) = ^{15}C_{4} * (75\%)^4 * (1 - 75\%)^{15 - 4} = 1365 * (0.75)^4 * (0.25)^{11} = 0.000103$

So, we have:

$P(x < 5) = (9.31 * 10^{-10}) + (4.19 * 10^{-8}) + (8.80 * 10^{-7}) + 0.0000153 + 0.000103$

$P(x < 5) = 0.00011922283$

Recall that:

$P(x \ge 5) = 1 - P(x < 5)$

$P(x \ge 5) = 1 - 0.00011922283$

$P(x \ge 5) = 0.9998$

$P(x \ge 5) = 1.000$ --- approximated

$(b)\ P(x = 15)$

$n = 15$ --- marketing personnel

$p = 75\%$ --- proportion that are extroverts

So, we have:

$P(x) = ^nC_x * p^x * (1 - p)^{n-x}$

$P(x=15) = ^{15}C_{15} * 0.75^{15} * (1 - 0.75)^{15-15}$

$P(x=15) = 1 * 0.75^{15} * (0.25)^{0$

$P(x=15) = 0.013$

$(c)\ P(x = 0)$

$n=5$ ---------- computer programmers

$p = 70\%$ --- proportion that are introverts

So, we have:

$P(x) = ^nC_x * p^x * (1 - p)^{n-x}$

$P(x = 0) = ^{5}C_0 * (70\%)^0 * (1 - 70\%)^{5-0}$

$P(x = 0) = 1 * 1 * (0.30)^5$

$P(x = 0) = 0.002$

3 0

3 years ago

What is the missing number in the sentence below?

Karolina [17]

The correct answer is A: 3. This is because...
3 * 4 = 12
12 * 5 = 60
Therefore, the answer is 60.

3 0

3 years ago

If A = {w.a, t,c, h, d, 0,8} and U = {a,b,c,d, e, f, g, h, L.), k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z), find A'

Ugo [173]

Adcdefghijklmnopqrstuvwxyz

6 0

4 years ago

What is the common difference for the sequence shown below? coordinate plane showing the points 1, 5; 2, 2; and 3, negative 1?

vodka [1.7K]

The correct answer to this problem would be -3. Based on the points you've provided on the graph, -3 would be the correct common difference. :)

5 0

3 years ago

Read 2 more answers

Can someone help me please

vodomira [7]

Answer:

DNE

Step-by-step explanation:

The left limit is +1; the right limit is -1. These are different, so the limit does not exist.

3 0

3 years ago