Step 1 :Looking at the given data, we see that increasing $t$ by five results in an increase in $P(t)$ of $1175$. Thus for every increase in $t$ of $1$, $P(t)$ increases by $\frac{1175}{5}=235$.
Step 2 :If $t = 3$ gives $P(t) = 1285$, then $t = t$ gives $P(t) = 1285 + (t-3)\cdot 235$.
Step 3 :So the equation that correctly represents this situation is $P(t) = 1285 + (t-3)\cdot 235$.
Step 4 :Simplify the equation, we get $P(t) = \boxed{235t + 435}$.