|
|
GMAT 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.
22 Jul 2022, 03:06
Kudos
Bookmarks
A
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
45%
(medium)
Question Stats:
71% (02:38) correct
29%
(02:43)
wrong
based on 207
sessions
History
Date
Time
Result
Not Attempted Yet
Erin travels 42 miles to and from work along the same route. One morning, she averaged a speed of 45 mph going to work and 67.5 mph coming home. What is the average speed for the round trip?
A. 54
B. 56
C. 68
D. 60
E. 64
A. 54
B. 56
C. 68
D. 60
E. 64
22 Jul 2022, 07:44
Kudos
Bookmarks
Bunuel
Since, the distance is same;
\(\frac{2*45*67.5}{45+67.5}\)
22 Jul 2022, 18:47
Kudos
Bookmarks
Bunuel
Remember that average speed = (total distance)/(total time).
Since she travels 42 miles each way, total distance is 42 + 42 = 84. Going to work, she travels at 42 miles at 45 mph, so this leg of the journey takes 42/45 hours. Similarly, she travels 42 miles at 67.5 coming home, so this leg of the journey takes 42/67.5 = 84/135 = 28/45 hours. Thus:
\(\Rightarrow\) (total distance)/(total time)
\(\Rightarrow\) 84/(42/45 + 28/45)
\(\Rightarrow\) 84/(70/45)
\(\Rightarrow\) (84 * 45)/70
\(\Rightarrow\) (12 * 45)/10
\(\Rightarrow\) 6 * 9 = 54 mph
Notice that the distance of 42 miles is irrelevant in this question. The answer will be the same for any other value, as long as she travels an equal amount of distance in each way.
Answer: A
