A sample of restaurants in a city showed that the average cost of a glass of iced tea is $1.25 with a standard deviation of 7¢. If a new restaurant charges a price for iced tea that has a z-value of - 1.25, then what is the tea's actual cost?

The tea's actual cost is $116.25

Step-by-step explanation:

* Lets revise how to find the z-score

- The rule the z-score is z = (x - μ) / σ, where

# x is the score

# μ is the mean

# σ is the standard deviation

* Lets solve the problem

- The average cost of a glass of iced tea is $1.25

- The standard deviation of it is 7 cents

- A new restaurant charges a price for iced tea that has a

z-value of - 1.25

* Lets change the average cost to cent

∵ $1 = 100 cents

∴ The average cost of a glass of iced tea = 1.25 * 100 = 125 cents

∵ z = (x - μ) / σ

∵ z = - 1.25

∵ μ = 125

∵ σ = 7

∴ - 1.25 = (x - 125) / 7 ⇒ multiply both sides by 7

∴ - 8.75 = x - 125 ⇒ add 125 to both sides

∴ 116.25 = x

* The tea's actual cost is $116.25

Answer: It is actually 1.16$ (The guy below accidentally added an extra 1)