Boris will rent a car for the weekend. He can choose one of two plans. The first plan has an initial fee of $\$ 65$ and costs an additional $\$ 0.60$ per mile driven. The second plan has no initial fee but costs $\$ 0.70$ per mile driven. How many miles would Boris need to drive for the two plans to cost the same?

Step 1 ：Let's denote the number of miles Boris needs to drive as x. The total cost of the first plan is \( \$65 + \$0.60x \) and the total cost of the second plan is \( \$0.70x \).

Step 2 ：We need to find the value of x for which the total cost of both plans is the same. We can set up the following equation to represent this situation: \( \$65 + \$0.60x = \$0.70x \).

Step 3 ：Solving this equation gives us the value of x as 650. This means that Boris would need to drive 650 miles for the two plans to cost the same.

Step 4 ：Final Answer: \(\boxed{650}\).