Answer:
C: 40 mph
Step-by-step explanation:
We are told that it took Matt twice the time to drive from home to work as it took him to drive from work to home.
This means;
2(time to drive from home to work) = time to drive from work to home
2(30) = time to drive from work to home
time to drive from work to home = 60 hr
We are told it took Matt 30 miles/hr to drive from home to work.
Thus;
Time from home to work = x/30 hours
Time to drive from work to home = x/60
Total distance = x + x = 2x
Thus,average speed = 2x/(x/30 + x/60) = 2x/(3x/60) = 120x/3x = 40 mph