Answer:

Step-by-step explanation:
Given

-- City C
--- City K
Required
Determine the 90% confidence interval
This is calculated using:

Calculating 




For a 90% confidence level, the z-score is 1.65. So:

Calculating the standard deviation 

So:


So:


Answer:
y is equal to -1
x is equal to 4
Step-by-step explanation:
The first thing you would do is multiply the bottom equation by a negative 3. You will get - 6x - 9y = -15. Keep the top equation the same. Both of the 6x's cancel. You then get -11y = 11 so y is equal to negative 1.
Since you have Y, you can now plug that in to any equation to find the value of x. -6x - 2(-1) = 26. You're left with 4. Plug both of the values into each equation to double check.
Answer: The equation that represents the give situation is, y = 0.75 x + 12
Step-by-step explanation:
Here, x represents the number of batteries the child bought and y represents the total cost.
Since, the cost of one batteries = $ 0.75
⇒ The cost of x batteries = 0.75 x
The cost of one toy = $ 12
Hence, the total cost = The cost of one toy + The cost of x batteries
= y = 0.75 x + 12
Which is the required equation that represents the given situation.