Answer:
n > 96
Therefore, the number of samples should be more than 96 for the width of their confidence interval to be no more than 10mg
Step-by-step explanation:
Given;
Standard deviation r= 25mg
Width of confidence interval w= 10mg
Confidence interval of 95%
Margin of error E = w/2 = 10mg/2 = 5mg
Z at 95% = 1.96
Margin of error E = Z(r/√n)
n = (Z×r/E)^2
n = (1.96 × 25/5)^2
n = (9.8)^2
n = 96.04
n > 96
Therefore, the number of samples should be more than 96 for the width of their confidence interval to be no more than 10mg
The volume of the car is 1800cm^3 which is equivalent to 0.0018m^3
<h3>Scale modelling</h3>
Given the scale factor that model of a car is amde to a scale of 1:40, Giving that the model as 45cm^3, this means that;
1 = 45cm^2
Determine the volume of the car
40 = x
Find the ratio
1/40 = 45/x
x = 40*45
x = 1800cm^3
x = 0.0018m^3
Hence the volume of the car is 1800cm^3 which is equivalent to 0.0018m^3
Learn more on scale factor here; brainly.com/question/25722260
#SPJ1
Ok, so;
Let me draw the figure here below:
We know that the area of a circle can be found using the next equation:
Area = πr².
Where r is the radius and π is a number.
So, the area of this circle, will be:
Area = π(1km)²
Area = π km²
<span>Area of circular metal=πr^2
=3.14 x 3.5 x 3.5 m^2
now,
total cost=area x rate
=3.14 x 3.5 x 3.5 x 3.25 $
=125.01 $</span>
