Has the marrying age of a man changed over the years? The United States Bureau of the Census takes a formal count of everyone in the U. S. every 10 years and has provided the following data that gives the median age of an American man at the time of his first marriage.

Year
1910
1920
1930
1940
1950
1960
1970
1980
1990
2000
Median Age
25.1
24.6
24.3
24.3
22.8
22.8
23.2
24.7
26.1
26.8

Is the average rate of change zero over any ten-year period? If so, when?
a.
Yes, 1930 - 1940
b.
Yes, 1950 - 1960
c.
Yes, both 1930 - 1940 and 1950 - 1960
d.
No

yes, there is no or zero rate of average change in the 1950 - 1960 ten-year period

ok

step-by-step explanation:

the value of v.w= -12.

step-by-step explanation:

we are given three vector r,v and w as:

r = < 5, -5, -2> ; v = < 2, -8, -8> ; w = < -2, 6, -5>

we know that r,v and w could also be represented as:

r=5i-5j-2k

v=2i-8j-8k

and w= -2i+6j-5k

where i,j and k are the unit vectors of x,y and z-axis respectively.

also we know that it has the following property:

i.i=1 ; j.j=1; k.k=1

and i.=j.i=i.k=k.i=j.k=k.j=0

i.e. when we multiply two vectors or we find it's dot product we need to only multiply the components of x coordinates with each other; y with each other and z with each other.

hence, v.w= (2i-8j- -2i+6j-5k)

                  = 2×(-2)+(-8)×(6)+(-8)×(-5)

                  = -4-48+40

                  = -12

hence, v.w= -12