Answer:
The probability of finding a sample mean less than 18 hours is 0.0082
Step-by-step explanation:
To find the probability of finding a sample mean less than 18 hours, we need to calculate the z-score of this sample mean 18. And the probability of finding a sample mean less than 18 hours is P(z<z(18)).
Z-score can be calculated as follows:
z(18)=
where
- X is the sample mean (18 hours)
- M is the average hours dentists spend per week on fillings (20 hours)
- s is the standard deviation (10 hours)
- N is the sample size (144)
Putting the numbers, we get:
z(18)=
Using z- table we can find that P(z<z(18)) = 0.0082
Considering the area of a rectangle, it is found that the area of Bob's remaining plot of land is of 12.5 acres.
<h3>What is the area of a rectangle?</h3>
The area of a rectangle of length l and width w is given by the multiplication of these dimensions, that is:
A = lw.
In this problem, both the length and the width are divided in half, hence the proportion remaining is given by:
A = 0.5l x 0.5w = 0.25lw = 25% of the initial area.
Hence:
0.25 x 50 = 12.5.
The area of Bob's remaining plot of land is of 12.5 acres.
More can be learned about the area of a rectangle at brainly.com/question/10489198
#SPJ1
The slope of a line perpendicular to another line has a
slope which is the negative reciprocal of that line or:
m1 = -1/m2
First, we convert the given equation into slope-intercept
form of a line: y = mx + b
8x + 15y = 12
15y = -8x + 12
y = (-8/15) x + 0.8
m1 = -8 / 15
Therefore the slope of the perpendicular line is:
m2 = 15 / 8
Since the perpendicular line crosses the point (11, 17), therefore
using the slope formula:
m = (y2 – y1) / (x2 – x1)
15 / 8 = (y2 – 17) / (x2 – 11)
1.875 (x2 – 11) = y2 – 17
1.875 x2 – 20.625 = y2 – 17
y2 = 1.875 x2 – 3.625
y = (15/8) x – 3.625
multiplying both sides by 8:
8y = 15x – 29
rewriting in standard form:
<span>15x – 8y = 29 (ANSWER)</span>
