Answer:
Explanation:
I hope these are people in vehicles travelling toward each other.
80 mh * t + 40 mph * t = 420 miles
The two vehicles are going to travel a total of 420 miles. B will cover a lot more ground than A, but together they will make 420 miles
80t + 40t = 420
120t = 420
t = 420/120
t = 3.5
So after driving 3.5 hours, the two cars will meet.