Maria drove to work at 70mph. Her average speed on the return trip was 60mph. The return trip took 1/2 an hour longer because of heavy traffic. How far did she travel to work?

210 miles

Step-by-step explanation:

Distance = rate * time

Going to work:

d = 70t

Returning from work:

d = 60 (t + ½)

d = 60t + 30

Since the distances are the same:

70t = 60t + 30

10t = 30

t = 3

Solving for distance:

d = 70t

d = 210

She drove 210 miles to work.