Step 1 :Identify the independent variable as time $(t)$, in months, and the dependent variable as amount paid $(p)$, in dollars. The linear function that models this situation is $p=310t + 900$.
Step 2 :This equation represents the total cost of leasing a car for $t$ months. The $310t$ term represents the monthly cost of the lease, and the $900$ represents the initial down payment and processing fee.
Step 3 :To find out for how many months you can lease the car with $3160, set $p$ equal to $3160$ and solve for $t$.
Step 4 :Substitute $3160$ into the equation: $3160 = 310t + 900$.
Step 5 :Subtract $900$ from both sides to get: $2260 = 310t$.
Step 6 :Divide both sides by $310$ to solve for $t$: $t = \frac{2260}{310} = 7.29$ months.
Step 7 :Since you can't lease a car for a fraction of a month, round down to the nearest whole number. Therefore, you can lease the car for 7 months with $3160$.
Step 8 :\(\boxed{7}\) is the final answer.