Answer:
5 mph
Step-by-step explanation:
c+15+c=2c+15 mph going down stream.
2.4(2c+15)=60
4.8c+36=60
4.8c=24
Simplifying
b2 + -4b + -14 = 0
Reorder the terms:
-14 + -4b + b2 = 0
Solving
-14 + -4b + b2 = 0
Solving for variable 'b'.
Begin completing the square.
Move the constant term to the right:
Add '14' to each side of the equation.
-14 + -4b + 14 + b2 = 0 + 14
Reorder the terms:
-14 + 14 + -4b + b2 = 0 + 14
Combine like terms: -14 + 14 = 0
0 + -4b + b2 = 0 + 14
-4b + b2 = 0 + 14
Combine like terms: 0 + 14 = 14
-4b + b2 = 14
The b term is -4b. Take half its coefficient (-2).
Square it (4) and add it to both sides.
Add '4' to each side of the equation.
-4b + 4 + b2 = 14 + 4
Reorder the terms:
4 + -4b + b2 = 14 + 4
Combine like terms: 14 + 4 = 18
4 + -4b + b2 = 18
Factor a perfect square on the left side:
(b + -2)(b + -2) = 18
Calculate the square root of the right side: 4.242640687
Break this problem into two subproblems by setting
(b + -2) equal to 4.242640687 and -4.242640687. b + -2 = 4.242640687
Simplifying
b + -2 = 4.242640687
Reorder the terms:
-2 + b = 4.242640687
Solving
-2 + b = 4.242640687
Solving for variable 'b'.
Move all terms containing b to the left, all other terms to the right.
Add '2' to each side of the equation.
-2 + 2 + b = 4.242640687 + 2
Combine like terms: -2 + 2 = 0
0 + b = 4.242640687 + 2
b = 4.242640687 + 2
Combine like terms: 4.242640687 + 2 = 6.242640687
b = 6.242640687
Simplifying
B = 6.242640687
Subproblem 2
b + -2 = -4.242640687
Simplifying
b + -2 = -4.242640687
Reorder the terms:
-2 + b = -4.242640687
Solving
-2 + b = -4.242640687
Solving for variable 'b'.
Move all terms containing b to the left, all other terms to the right.
Add '2' to each side of the equation.
-2 + 2 + b = -4.242640687 + 2
Combine like terms: -2 + 2 = 0
0 + b = -4.242640687 + 2
b = -4.242640687 + 2
Combine like terms: -4.242640687 + 2 = -2.242640687
b = -2.242640687
Simplifying
b = -2.242640687
The mean is the average.
To find the mean, you add up all the numbers, and then divide by the number of numbers.
:P
Answer:
I think the answer is B. 65%
Step-by-step explanation:
i don't know though
a. Find the probability that an individual distance is
greater than 214.30 cm
We find for the value of z score using the formula:
z = (x – u) / s
z = (214.30 – 205) / 8.3
z = 1.12
Since we are looking for x > 214.30 cm, we use the
right tailed test to find for P at z = 1.12 from the tables:
P = 0.1314
b. Find the probability that the mean for 20 randomly
selected distances is greater than 202.80 cm
We find for the value of z score using the formula:
z = (x – u) / s
z = (202.80 – 205) / 8.3
z = -0.265
Since we are looking for x > 202.80 cm, we use the
right tailed test to find for P at z = -0.265 from the tables:
P = 0.6045
c. Why can the normal distribution be used in part (b),
even though the sample size does not exceed 30?
I believe this is because we are given the population
standard deviation sigma rather than the sample standard deviation. So we can
use the z test.