Acar traveling at 70 miles per hour traveled one hour longer than a truck traveling 60 miles per hour. if the car and truck traveled a total of 330 miles, for how many hours did the car and truck travel all together

Well, if the truck traveled for one hour, that means the car traveled for two.
60+70+70=200
It's not that difficult to just guess and check, even if it's a bit time consuming.
Let's try three hours for the truck.
60+60+60+70+70+70+70=460
That's too much, so we'll try two hours.
60+60+70+70+70=330
The truck traveled two hours, and the car traveled three hours, since the car traveled one hour longer than the truck.
All together, the car and truck drove a total of 5 hours.

Maybe the answer is 20mm. all i really did was just multiply, which is obvious.