Answer:
c) P(270≤x≤280)=0.572
d) P(x=280)=0.091
Step-by-step explanation:
The population of bearings have a proportion p=0.90 of satisfactory thickness.
The shipments will be treated as random samples, of size n=500, taken out of the population of bearings.
As the sample size is big, we will model the amount of satisfactory bearings per shipment as a normally distributed variable (if the sample was small, a binomial distirbution would be more precise and appropiate).
The mean of this distribution will be:

The standard deviation will be:

We can calculate the probability that a shipment is acceptable (at least 440 bearings meet the specification) calculating the z-score for X=440 and then the probability of this z-score:

Now, we have to create a new sampling distribution for the shipments. The size is n=300 and p=0.932.
The mean of this sampling distribution is:

The standard deviation will be:

c) The probability that between 270 and 280 out of 300 shipments are acceptable can be calculated with the z-score and using the continuity factor, as this is modeled as a continuos variable:

d) The probability that 280 out of 300 shipments are acceptable can be calculated using again the continuity factor correction:

9514 1404 393
Answer:
(a) x = (3 -ln(3))/5 ≈ 0.819722457734
(b) y = 10
Step-by-step explanation:
(a) Taking the natural log of both sides, we have ...
2x +1 = ln(3) +4 -3x
5x = ln(3) +3 . . . . . . . . add 3x-1
x = (ln(3) +3)/5 ≈ 0.820
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(b) Assuming "lg" means "log", the logarithm to base 10, we have ...
log(y -6) +log(y +15) = 2
(y -6)(y +15) = 100 . . . . . . . taking antilogs
y^2 -9x -190 = 0 . . . . . . . . eliminate parentheses, subtract 100
(y -19)(y +10) = 0 . . . . . . . . factor
The values of y that make these factors zero are -19 and 10. We know from the first term that (y-6) > 0, so y > 6. That means y = -19 is an extraneous solution.
The solution is ...
y = 10
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When solving equations using a graphing calculator, it often works well to define a function f(x) such that the solution is f(x) = 0, the x-intercept(s). That form is easily obtained by subtracting the right side of the equation from both sides of the equation. In part (a) here, that is ...
f(x) = e^(2x+1) -3e^(4-3x)
The value of
is 31
Explanation:
The given expression is 
We need to determine the value of 
The value of
can be determined by substituting
in the expression 
Thus, we have,

Adding the terms, we have,

Thus, the value is 31.
Therefore, the simplified value of the expression by substituting
in the expression
is 31.
1.25 kilograms=2.755778 pounds
Answer:
Andres saved the greatest amount of money each week
Explanation:
Andres saved $2 each week
Carla saved $1.75 each week
Andres's graph shows +2 each week
Carla's table shows an increase of +1.75 each week
2 > 1.75