Physics word problem

Question

Alan leaves LA at 8:00am to drive to to San Fran 400 miles away. He travels at a steady 50mph. Beth leaves LA at 9:00am and drives a steady 60mph. 

 

a) Who gets to San Fransisco first?

b) How long does the first to arrive have to wait for the second?

 

For a) when i did my calculations, I found Beth got there first. Its part b I dont know how to do?

Answer 1

Beth arrived at 3:40 pm. Correct?

Alan arrived at 4:00 pm. Correct?

How long did Beth wait until Alan arrived?

Answer 2

Alan:

 

400 mi / 50 mi/hr = 8 hr

 

Beth:

 

400 mi / 60 mi/hr = 6.666.. hr

 

So from here you can see that Beth, having left only an hour later arrives earlier

 

From here, you should convert hours to minutes.

 

60 mi/hr * 1 hr / 60 min = 1 mi/min

 

400 mi / 1 mi/min = 400 min

 

6 hrs = 360 min

 

So Beth takes 6 hrs and 40 min.

9 am + 6hr and 40 min = 3:40 pm

 

Alan takes 8 hrs.

8 am + 8 hrs = 4 pm

 

That means Beth having left an hour later, waits only 20 min for Alan to arrive.