13. A class of 195 students went on a fieldtrip. They took 7 vehicles, some cars and some buses. Find the number of cars and the number of buses they took if each car holds 5 students, and each bus holds 45 students.

Step 1 ：Let's denote the number of cars as x and the number of buses as y.

Step 2 ：We know that the total number of vehicles is 7, so we have the equation \(x + y = 7\).

Step 3 ：We also know that the total number of students is 195, and each car holds 5 students and each bus holds 45 students, so we have the equation \(5x + 45y = 195\).

Step 4 ：We can solve this system of equations to find the values of x and y.

Step 5 ：The solution to the system of equations is x = 3 and y = 4. This means that the class took 3 cars and 4 buses on the field trip.

Step 6 ：Final Answer: The number of cars is \(\boxed{3}\) and the number of buses is \(\boxed{4}\).