Question

Laura babysat 8 nights during the month of July. She earned $22, $30, $35, $25, $25, $20, and $27 for seven nights. How much did she earn the eighth time if the mean of the data is $26.50?

Answer 1

Answer:

$28

Step-by-step explanation:

Given:

data = [22,30,35,25,25,20,27]

For eight night, the new list is:

new_data = [22,30,35,25,25,20,27,x]

Mean = 26.50

Mean Formula:

$\displaystyle \large{m=\dfrac{x_1+x_2+x_3+...+x_n}{n} }$

Therefore:

$\displaystyle \large{26.50=\dfrac{22+30+35+25+25+20+27+x}{8}}$

Multiply both sides by 8:

$\displaystyle \large{26.50\cdot 8=\dfrac{22+30+35+25+25+20+27+x}{8} \cdot 8}\\\displaystyle \large{212=22+30+35+25+25+20+27+x}$

Solve for x:

$\displaystyle \large{212=22+30+35+25+25+20+27+x}\\\displaystyle \large{212=184+x}$

Subtract 184 both sides:

$\displaystyle \large{212-184=184+x-184}\\\displaystyle \large{28=x}$

Therefore, she will earn $28 in eighth night

The attachment below is the result of combining all eighth data as we get 26.5 through python language with numpy package.

Answer 2

Answer: $28.

Step-by-step explanation: To solve this problem, we should first find the mean of the data with the seven payments that are given already:

22 + 30 + 35 + 25 + 25 + 20 + 27 = 184.

184 / 7 = 26.2857142857.

In order to figure out how much she made the eighth night with the mean of the data being $26.50, we can pick a number and add it to 184 (the total of the seven payments), and divide the total by 8.  The number we can try is 28. The work is done below:

184 + 28 = 212.

212 / 8 = $26.50.

Therefore, Laura's payment on the eighth night was $28.

Hope this helps! :)