Mr. Williams starts out in his auto traveling 30 miles per hour. Four hours later, Mr. Speedster starts out at the same point at 60 miles per hour to overtake Mr. Williams. In how many hours will he be overtaken?
- print Print
- list Cite
Expert Answers
calendarEducator since 2013
write619 answers
starTop subjects are Math, Science, and Literature
Since Mr. Williiams travels at 30 mph, in after time t (in hours) have elapsed, he will have traveled the distance d
d = 30t
Mr. Speedster starts out at the same point 4 hours later at 60 mph. So after time t have elapsed since Mr. Speedster started, he will have traveled for t - 4 hours and covered the distance 60(t-4).
At the time t when Mr. Speedster overtakes Mr. Williams, they will have traveled the same distance d:
d = 30t = 60(t - 4)
Solve this equation for t:
30 t = 60t - 240
-30t =-240
t = 8
8 hours have elapsed since Mr. Williams started traveling, so 8 - 4 = 4 hours have elapsed since Mr. Speedster started traveling.
Mr. Speedster will overtake Mr. Williams in 4 hours.
This means Mr. Speedster will overtake Mr. Williams in 8 hours after
Related Questions
- Brian drove 120 miles at speed of 60 miles per hour. He drove the same distance back home at home...
- 1 Educator Answer
- A long distance runner starts at the beginning of a trail and runs at a rate of 5 miles per hour....
- 1 Educator Answer
- Two cars are driving towards each other from towns that are 150 miles apart. The first car is...
- 1 Educator Answer
- An airplane flies at an altitude of y = 5 miles toward a point directly over an observer. The...
- 2 Educator Answers
- Johnny drove at 32 miles per hour for 30 minutes and at 48 miles per hour for 45 minutes. How far...
- 2 Educator Answers