Algebra Question

A company rents moving trucks out of two locations: Detroit and San Antonio. Some of their customers rent a truck in one city and return it in the other city, and the rest of their customers rent and return the truck in the same city. The company owns a total of 400 trucks.

The company has seen the following trend:

About 70 percent of the trucks in Detroit move to San Antonio each week.
About 55 percent of the trucks in San Antonio move to Detroit each week.
Suppose right now Detroit has 140 trucks.

How many trucks will be in each city after 1 week? [Round answers to the nearest whole number.]
Detroit:
San Antonio:

How many trucks will be in each city after 4 weeks? [Round answers to the nearest whole number.]
Detroit:
San Antonio:

If the vector [te[tex]\left[\begin{array}{ccc}1&2&3\\4&5&6\\7&8&9\end{array}\right][/tex] resents the distribution of trucks, where x1 is the number in Detroit and x2 is the number in San Antonio, find the matrix A so that At is the distribution of trucks after 1 week.