Answer:
The probability that the sample mean will lie within 2 values of μ is 0.9544.
Step-by-step explanation:
Here
- the sample size is given as 100
- the standard deviation is 10
The probability that the sample mean lies with 2 of the value of μ is given as
Here converting the values in z form gives
Substituting values
From z table
So the probability that the sample mean will lie within 2 values of μ is 0.9544.
Answer: b
Step-by-step explanation:
In the last question, you wrote on a second equation "13x ...." kkk
Let's go:
We have to check each one answer in the following system:
x - 2y = 7
3x + 7y = 8
I can use the substituition method to solve this system...
x = 7 + 2y
3x + 7y = 8
3(7 + 2y) + 7y = 8
21 + 6y + 7y = 8
13y = 8 - 21
13y = -13
y = -1
x = 7 + 2.(-1)
x = 5
Finally, the correct answer is the second one (letter b).
Answer:
Sphere Volume = 4/3 * PI * radius^3
Sphere Volume = 4/3 * PI * 8^3
Sphere Volume = 4/3 * PI * 512
Sphere Volume = 2,144.7 cubic inches
Step-by-step explanation:
<span>let x = the original no. of students
then
(x+10) = the actual no. that went on the trip
:
= the original cost per student
and
= the actual cost
:
Original cost - actual cost = $12.50
- = 12.50
multiply equation by x(x+10)
x(x+10)* - x(x+10)* = 12.50x(x+10)
Cancel the denominators
1500(x+10) - 1500x = 12.5x(x+10)
1500x + 15000 - 1500x = 12.5x^2 + 125x
Combine on the right to form a quadratic equation
0 = 12.5x^2 + 125x - 15000
Simplify, divide equation by 12.5
x^2 + 10x - 1200 = 0
You can use the quadratic formula; a=1; b=10; c=-1200, but this will factor to
(x + 40(x - 30) = 0
The positive solution is what we want here
x = 30 students in the original group
Check this by finding the cost per student for each scenario
1500/30 = $50.00; original cost
1500/40 = $37.50; actual cost
---------------------
saving: $12.50</span>
