That is the correct expression but not the correct answer.
504 divided by 3 is 168.
I hope this helped! :-)
Answer:
Input
Independent variable
Step-by-step explanation:
we know that
<u><em>Independent variables</em></u>, are the values that can be changed or controlled in a given model or equation
<u><em>Dependent variables</em></u>, are the values that result from the independent variables
we have the function

In this problem
The function d(t) represent the dependent variable or the output
The variable t represent the independent variable or input
PS = PR+RS
PS = 18.8+13.7 = 32.5