GRE Prep Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.
Customized
for You
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Andrew drove from A to B at 60 miles per hour. Then he realized that h
[#permalink]
27 Feb 2023, 02:57
27 Feb 2023, 02:57
1
Expert Reply
1
Bookmarks
00:00
Question Stats:
71% (02:39) correct
28% (03:46) wrong based on 7 sessions
Hide Show timer Statistics
Andrew drove from A to B at 60 miles per hour. Then he realized that he forgot something at A, and drove back at 80 miles per hour. He then zipped back to B at 90 mph. What was his approximate average speed in miles per hour for the entire trip?
Show: ::
74.5
Re: Andrew drove from A to B at 60 miles per hour. Then he realized that h
[#permalink]
18 Mar 2023, 03:13
18 Mar 2023, 03:13
Expert Reply
OE
Use a Multiple RTD chart to solve this problem. Start by selecting a Smart Number for d, such as 720 miles. (This is a common multiple of the 3 rates in the problem.) Then work backward to find the time for each trip and the total time:
Ta=720/60=12 hrs
Tb=720/80=9 hrs
Tc=720/90=8 hrs
T= 29 hrs
Average speed\(=\frac{2,160}{29} \approx 74.5\) miles per hr
Use a Multiple RTD chart to solve this problem. Start by selecting a Smart Number for d, such as 720 miles. (This is a common multiple of the 3 rates in the problem.) Then work backward to find the time for each trip and the total time:
Ta=720/60=12 hrs
Tb=720/80=9 hrs
Tc=720/90=8 hrs
T= 29 hrs
Average speed\(=\frac{2,160}{29} \approx 74.5\) miles per hr
gmatclubot
Re: Andrew drove from A to B at 60 miles per hour. Then he realized that h [#permalink]
18 Mar 2023, 03:13
Moderators:
