Answer:
The depth of snow at 9:00 am was 19 inches.
Step-by-step explanation:
Consider the provided information.
Let x represents the number of hours and S(x) represents the depth of snow.
There was no snow on the ground when it started falling at midnight at a constant rate of 1.5 inches per.
That means the depth of snow will be:
[tex]S(x)=1.5x\ \ \ 0\leq x< 4[/tex]
At 4:00 a.m., it starting falling at a constant rate of 3 inches per hour,
[tex]S(x)=3(x-4)+6\ \ \ 4\leq x<7 [/tex]
7:00 a.m. to 9:00 a.m., snow was falling at a constant rate of 2 inches per hour.
[tex]S(x)=2(x-7)+15\ \ \ 7\leq x\leq 9 [/tex]
The required piece-wise linear function is
[tex]\left\{\begin{matrix}1.5x & 0\leq x<4\\ 3(x-4)+6 & 4\leq x<7\\ 2(x-7)+15 & 7\leq x\leq 9\end{matrix}\right.[/tex]
We need to find the how deep was the snow at 9:00 am
For 9:00 am we will choose the function which can take the value of x=9
Substitute the value of x=9 in [tex]S(x)=2(x-7)+15[/tex]
[tex]S(x)=2(9-7)+15[/tex]
[tex]S(x)=2(2)+15[/tex]
[tex]S(x)=19[/tex]
Hence, the depth of snow at 9:00 am was 19 inches.