Answer:

Step-by-step explanation:
The function that could model this periodic phenomenon will be of the form

The tide varies between 3ft and 9ft, which means its amplitude
is

and its midline
is
.
Furthermore, since at
the tide is at its lowest ( 3 feet ), we know that the trigonometric function we must use is
.
The period of the full cycle is 14 hours, which means


giving us

With all of the values of the variables in place, the function modeling the situation now becomes

Step-by-step explanation:

Well you gotta ask the chair politely, "how old are you chair?"
Answer:
$170
Step-by-step explanation:
15 percent of 200 is 30 and 30 minus 200 would be 170