Question

Theodora drove on the blue ridge parkway at 40 mph and then on the interstate highway at 70 mph. She drove three times as long on the blue ridge parkway as she did on the interstate. If she drove a total of 285 mi, for how long did she drive on the interstate?

Answer 1

3x × 40+ x × 70 = 285
120x + 70x = 285
190x = 285
x = 285/190
x = 1.5
Theodory traveled at the interstate for 1.5 hours