Answer:
The sample size is
Step-by-step explanation:
From the question we are told that
The lower bound of the range is a = 51
The upper bound of the range is b = 710
The margin of error is 
Generally the standard deviation is mathematically represented as

=> 
=> 
From the question we are told the confidence level is 95% , hence the level of significance is
=>
Generally from the normal distribution table the critical value of
is
Generally the sample size is mathematically represented as
=>
=>
In January the price of brand x rice was 2$.
The number of 11-inch softball is 70 and the number of 12-inch softball is 50.
<u>Step-by-step explanation</u>:
<u>Given that,</u>
- The cost of 11-inch softball = $2.50
- The cost of 12-inch softball = $3.50
<u>Let us assume,</u>
- The number of 11-inch softball be 'x'.
- The number of 12-inch softball be 'y'.
<u>Forming the equation to solve x and y values :</u>
- The total number of softball ordered = 120
- The total cost for 120 softballs = $350
x + y = 120 -------(1)
2.5x + 3.5y = 350 --------(2)
<u>Multiply eq(1) by 2.5 and subtract eq(2) from eq(1)</u>,
2.5x +2.5y = 300
-<u>(2.5x +3.5y = 350)</u>
<u> -1y = -50</u>
Therefore the value of y = 50.
The number of 12-inch softball is 50.
<u>Substitute y=50 in eq(1),</u>
x+50 = 120
x = 120-50
x = 70
The number of 11-inch softball is 70.
The values of the variables are k = -6 , w = ± 9 , f = -7
Step-by-step explanation:
To solve these problems we will compare the elements inside the [ ]
[-12 , -w²] = [2k , -81]
[2f , 3] = [-14 , 3]
That mean:
1. -12 = 2k
2. -w² = -81
3. 2f = -14
∵ 2k = -12
Divide both sides by 2 to find k
∴ k = -6
∵ -w² = -81
Divide both sides by -1
∴ w² = 81
Take √ for both sides
∴ w = ± 9
∵ 2f = -14
Divide bith sides by 2
∴ f = -7
The values of the variables are k = -6 , w = ± 9 , f = -7
Learn more:
You can learn more about simple equation in brainly.com/question/13113987
#LearnwithBrainly