Answer:
About 3 years Speedy Jet printers be guaranteed.
Step-by-step explanation:
Given : Quality control studies for Speedy Jet Computer Printers show the lifetime of the printer follows a normal distribution with
mean
and standard deviation 
If the company wishes to replace no more than 10% of the printers.
To find : How long should Speedy Jet printers be guaranteed ?
Solution :
Using Z- table,
Z value corresponding to 10% or 0.10 = -1.28.
Applying z-score formula,

The value of x is given by,

Substitute the values,



So, approx 3 years.
Therefore, About 3 years Speedy Jet printers be guaranteed.
Answer:
6/13 7/13 chance to get the marbles
Step-by-step explanation:
Formula of the Volume of a hemisphere:
V =


r³
144

=


r³
Multiply by 3 to cancel fraction in the right side
144

× 3 = 2

r³
432

= 2

r³
Divide by 2

on either sides to isolate r³

=

r³
2

and

cancel out
216 = r³
Take cube root to find the radius
![\sqrt[3]{216}](https://tex.z-dn.net/?f=%20%5Csqrt%5B3%5D%7B216%7D%20)
=
![\sqrt[3]{r^3}](https://tex.z-dn.net/?f=%20%5Csqrt%5B3%5D%7Br%5E3%7D%20)
6 = r
Radius is 6 unitsThe formula of the surface area of a hemisphere is:
S.A = 2

r² +

r²
=

(6)² +

(6)²
=2

× 36 + 36

= 72

+ 36

= 108

units² (in terms of

)
≈ 339.12 units²
Surface area = 108
units
Answer:
made 25%
Step-by-step explanation: