Answer:
Mean = 21.3
Standard Deviation = 2.48
Step-by-step explanation:
We are given the following in the question:
p = 71% = 0.71
Sample size, n = 30
We have to find the mean and the standard deviation of those that wear glasses.
Thus, the mean of those who wear glasses is 21.3
Thus, the standard deviation of those who wear glasses is 2.48
Answer:
The systems of equation are .
Vanessa worked for<u> 6 hrs </u>and Geneva worked for <u>15 hrs</u> to earn exactly $240.
Step-by-step explanation:
Let the number of hours worked by Vanessa be 'v'.
Let the number of hours worked by Geneva be 'g'.
Given:
Total number of hours worked = 21 hours
So we can say that;
Total number of hours worked is equal to sum of number of hours worked by Vanessa and number of hours worked by Geneva.
framing in equation form we get;
⇒ equation 1
Also given:
per hour earnings of Vanessa = $10
per hour earning of Geneva = $12
Total they need to earn = $240
So we can say that;
Total they need to earn would be equal to sum of per hour earnings of Vanessa multiplied by number of hours worked by Vanessa and per hour earning of Geneva multiplied by number of hours worked by Geneva.
framing in equation form we get;
⇒ equation 2
Hence The systems of equation are .
On Solving above equations we get;
First we will multiply equation 1 by 10 we get;
⇒ equation 3
Now Subtracting equation 3 from equation 2 we get;
Dividing both side by 2 we get;
Now Substituting the value of g in equation 1 we get;
Hence Vanessa worked for<u> 6 hrs </u>and Geneva worked for <u>15 hrs</u> to earn exactly $240.