Answer:
a) We need to find p(x<68.15)
Standardize x to z, we have, z = (68.15-μ)/σ
=(68.15-57)/8.1
=1.38
Reading from standard normal tables,
p(z<1.38) =0.9162.
b) We need to find p(x>54.4)
Standardize x to z, we have, z = (54.4-μ)/σ
=(54.4-57)/8.1
=-0.32
Reading from standard normal tables,
p(z>-0.32) = 0.6255
people need to watch out for their environment by not smoking, not littering, and such bad things like that.
The volume of the rectangular pyramid is 28 cubic feet.
<h3>
How to find the volume of the pyramid?</h3>
The volume of a pyramid of base B and height H is given by:

Here we know that the height is H = 7ft, and the base is a rectangle of 4ft by 3ft, so the area of the base is:

Then the volume of the pyramid is:

If you want to learn more about volumes:
brainly.com/question/1972490
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You learn new thing every day!!!
Explanation: