Answer:
The tea's actual cost is $116.25
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