Answer:
The error she made was that she was adding x and 2.75. She should subtract 2.75 from x.
Another mistake that she made was that she sold each for $7 assuming that she would make a profit of 78, but she should see each necklace for $12.5 so that she could make a profit of $78.
Step-by-step explanation:
The error she made was that she was adding x and 2.75.
She should write the equation as 8 (x - 2.75) = 78; as she spends $2.75 to make a necklace.
By using the correct equation: 8 (x - 2.75) = 78
=> 8x - 22 = 78
=> 8x = 78 + 22
=> 8x = 100
=> x = 100/8
=> x = 12.5
Another mistake that she made was that she sold each for $7 assuming that she would make a profit of 78, but she should see each necklace for $12.5 so that she could make a profit of $78.
Hope this helps you.
Answer: (60.858, 69.142)
Step-by-step explanation:
The formula to find the confidence interval for mean :
, where
is the sample mean ,
is the population standard deviation , n is the sample size and
is the two-tailed test value for z.
Let x represents the time taken to mail products for all orders received at the office of this company.
As per given , we have
Confidence level : 95%
n= 62
sample mean :
hours
Population standard deviation :
hours
z-value for 93% confidence interval:
[using z-value table]
Now, 93% confidence the mean time taken to mail products for all orders received at the office of this company :-

Thus , 93% confidence the mean time taken to mail products for all orders received at the office of this company : (60.858, 69.142)
Answer:
Step-by-step explanation:
Given that,
f(3) = 2
f'(3) = 5.
We want to estimate f(2.85)
The linear approximation of "f" at "a" is one way of writing the equation of the tangent line at "a".
At x = a, y = f(a) and the slope of the tangent line is f'(a).
So, in point slope form, the tangent line has equation
y − f(a) = f'(a)(x − a)
The linearization solves for y by adding f(a) to both sides
f(x) = f(a) + f'(a)(x − a).
Given that,
f(3) = 2,
f'(3) = 5
a = 3, we want to find f(2.85)
x = 2.85
Therefore,
f(x) = f(a) + f'(a)(x − a)
f(2.85) = 2 + 5(2.85 - 3)
f(2.85) = 2 + 5×-0.15
f(2.85) = 2 - 0.75
f(2.85) = 1.25