High-strength concrete is supposed to have a compressive strength greater than 6,000 pounds per square inch (psi). a certain type of concrete has a mean compressive strength of 7,000 psi, but due to variability in the mixing process it has a standard deviation of 420 psi, assuming a normal distribution.

Answer

given,

greater compressive strength = 6,000 psi

mean compressive strength(μ) = 7000 psi

standard deviation (σ) = 420 psi

P(X < 6000)                                              

Z = - 2.38                    

P(Z<-2.38) = Area to left - 2.38

from Z table                          

P(X < 6000) = P(Z<-2.38) = 0.0087

P(fail) = P(X< 6000) = 0.0087 = 0.87

multiply then divide

step-by-step explanation:

the answer would be d.

step-by-step explanation:

move all variables to the left side and all constants to the right side

(x−3)^2+(y−1)^2=16

this is the form of a circle. use this form to determine the center and radius of the circle.

( x − h ) 2 + ( y − k ) 2 = r 2

match the values in this circle to those of the standard form. the variable   r   represents the radius of the circle,   h   represents the x-offset from the origin, and   k   represents the y-offset from origin.

r = 4

h = 3

k = 1

the center of the circle is found at   ( h , k ) .

center:   ( 3 , 1 )

these values represent the important values for graphing and analyzing a circle.

center:   ( 3 , 1 ).

radius:   4