Aseem and Stana are building model cars. Stana's car is 5 less than 2 times the length of Aseem's car. The sum of the lengths of both cars is 20 inches. Write an equation to determine the lengths of Aseem's and Stana's cars.

2x − 5 + x = 20
5 − 2x + x = 20
2x − 5 = 20
5 − 2x = 20