Answer:
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:
The formula for the volume of a cylinder is V=Bh or V=πr2h . The radius of the cylinder is 8 cm and the height is 15 cm. Substitute 8 for r and 15 for h in the formula V=πr2h . Simplify.
Step-by-step explanation:
21x-y-49=0 is the equation
Answer:
5, 10, 15, 20, 25, 30
Step-by-step explanation:
I think this is a rule of pattern idk
Answer:
Step-by-step explanation:
hello :
z⁴=1+i given : z² = t t is the complex number so : z⁴= (z²)² =t²
solve for t this equation : t² = 1+i
if : t = x+iy t² =(x+iy)² = x²+2xiy+(iy)² =x²-y²+2xyi ...... ( i² = -1)
t² = 1+i means : x²-y²+2xyi = 1+i
you have this system : x²-y² = 1.....(*)
2xy = 1.....(**)
slve for x and y you ca add this equation : ....(***)
( use : t² = 1+i
/t²/ = /1+i/ so :/t/² = /1+i/ .... (√(x²+y²))²=√(1²+1²) =√2 means x²+y² = √2)
the system is : x²-y² = 1.....(*)
2xy = 1.....(**)
x²+y² = √2 ....(***)
add (*) and (***) : 2x²= 1+√2
x² = (√2+1)/2
substrac (*) and (***) you have : y² = (√2-1)/2
use (**) the proudect xy is positif (same sign) so :
x=√( (√2+1)/2) and y = √( (√2-1)/2) so : t1 =√( (√2+1)/2)+i√( (√2-1)/2)
x= -√( (√2+1)/2) and y = -√( (√2-1)/2) so :t2= -t1
same method for equation : z² =t1 ..(2 solution ) and z² = t2..(2 solution )