Compab=a.b/|a|
b=<0,1,−2√10>
a.b= 2√10
|a| = √10
a.b/|a|=2√10 / √10=2
As IQ scores for extensive populaces are focused at 100, the mean = 100.
There ought to be around half scores above or underneath the mean score since mean and middle is about a similar when the populace is substantial.
P(x > 100) = P( z> (100 - 100)/sd ) = P(z > 0)= 0.5
The number of the student who has scored over 100 = 0.5 x 78 = 39 Therefore the answer is 39 students.
For this case we have the following equation:

Where,
w: The weight of a spring in pounds
E: the energy stored by the spring in joules.
Substituting values we have:

Making the corresponding calculation:
Answer:
the approximate weight of the spring in pounds is:
B) 65.84 add 67.5 and 6.443 and divide sum by 1.123