To solve this problem, we use the formula:
z = (x – u) / s
where z is the z score value which can be obtained from
the tables, x is the sample value, u is the mean = 6.3 min, and s is the std
dev = 2.2 min
at P value = 0.90, the z = 1.28, finding for x:
x = z s + u
x = 1.28 * 2.2 + 6.3
x = 9.116
at P value = 1.0, the z = 3.49, finding for x:
x = z s + u
x = 3.49 * 2.2 + 6.3
x = 13.978 ~ 14
Therefore the longest 10% calls last about 9.1 minutes to
14 minutes
<span>So we want to know how much ball bearings can be made with 5.24 cm^3 if one ball bearing has a diameter of 1 cm. We know that radius r=d/2=0.5cm So the volume V of one ball bearing is: V=(4/3)*pi*r^3 so V=(4/3)*3.14*(0.5)^3cm^3=0.524cm^3. Now we simply divide the volume of steel by the volume of the ball bearing: 5.24/0.524=10. So we can make 10 ball bearings from 5.24 cm^3 of steel</span>
0.75 because 100cm = 1m so you just move the decimal to the right by 2
To solve the problem shown above you must apply the following proccedure:
1. You have the following function given in the problem:
<span> f(x)=x3–3x–2
2. When you give values to the x and plot each point obtained, you obtain the graph shown in the figure attached.
3. Based on the graph and analizing the alternate form:
f(x)=(x-2)(x+1)</span>²
As you can see, there is two roots x=-1, then, you can conclude that the correct answer is the option b, which is:
b) -1<span>
</span>