HELP ME [QUESTION IN IMAGE AND NOT THAT HARD EITHER]
2 answers:
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QUESTION 1
We want to solve,
We factor the denominator of the fraction on the right hand side to get,
This implies
We multiply through by LCM of
We expand to get,
We group like terms and equate everything to zero,
We split the middle term,
We factor to get,
But
is not in the domain of the given equation.
It is an extraneous solution.
is the only solution.
QUESTION 2
We add x to both sides,
We square both sides,
We expand to get,
This implies,
We solve this quadratic equation by factorization,
But
is an extraneous solution
We want to solve,
We factor the denominator of the fraction on the right hand side to get,
This implies
We multiply through by LCM of
We expand to get,
We group like terms and equate everything to zero,
We split the middle term,
We factor to get,
But
is not in the domain of the given equation.
It is an extraneous solution.
is the only solution.
QUESTION 2
We add x to both sides,
We square both sides,
We expand to get,
This implies,
We solve this quadratic equation by factorization,
But
is an extraneous solution
Answer:
(a) P(X > $57,000) = 0.0643
(b) P(X < $46,000) = 0.1423
(c) P(X > $40,000) = 0.0066
(d) P($45,000 < X < $54,000) = 0.6959
Step-by-step explanation:
We are given that U.S. Bureau of Economic Statistics reports that the average annual salary in the metropolitan Boston area is $50,542.
Suppose annual salaries in the metropolitan Boston area are normally distributed with a standard deviation of $4,246.
<em>Let X = annual salaries in the metropolitan Boston area</em>
SO, X ~ Normal()
The z-score probability distribution for normal distribution is given by;
Z = ~ N(0,1)
where, = average annual salary in the Boston area = $50,542
= standard deviation = $4,246
(a) Probability that the worker’s annual salary is more than $57,000 is given by = P(X > $57,000)
P(X > $57,000) = P( >
) = P(Z > 1.52) = 1 - P(Z
1.52)
= 1 - 0.93574 = <u>0.0643</u>
<em>The above probability is calculated by looking at the value of x = 1.52 in the z table which gave an area of 0.93574</em>.
(b) Probability that the worker’s annual salary is less than $46,000 is given by = P(X < $46,000)
P(X < $46,000) = P( <
) = P(Z < -1.07) = 1 - P(Z
1.07)
= 1 - 0.85769 = <u>0.1423</u>
<em>The above probability is calculated by looking at the value of x = 1.07 in the z table which gave an area of 0.85769</em>.
(c) Probability that the worker’s annual salary is more than $40,000 is given by = P(X > $40,000)
P(X > $40,000) = P( >
) = P(Z > -2.48) = P(Z < 2.48)
= 1 - 0.99343 = <u>0.0066</u>
<em>The above probability is calculated by looking at the value of x = 2.48 in the z table which gave an area of 0.99343</em>.
(d) Probability that the worker’s annual salary is between $45,000 and $54,000 is given by = P($45,000 < X < $54,000)
P($45,000 < X < $54,000) = P(X < $54,000) - P(X $45,000)
P(X < $54,000) = P( <
) = P(Z < 0.81) = 0.79103
P(X $45,000) = P(
) = P(Z
-1.31) = 1 - P(Z < 1.31)
= 1 - 0.90490 = 0.0951
<em>The above probability is calculated by looking at the value of x = 0.81 and x = 1.31 in the z table which gave an area of 0.79103 and 0.9049 respectively</em>.
Therefore, P($45,000 < X < $54,000) = 0.79103 - 0.0951 = <u>0.6959</u>