|
|
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.
03 Jan 2021, 07:57
Kudos
Bookmarks
C
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
15%
(low)
Question Stats:
84% (01:55) correct
16%
(02:02)
wrong
based on 116
sessions
History
Date
Time
Result
Not Attempted Yet
Yesterday it took a certain plane 3 hours to fly from City A to City B at an average speed of 400 miles per hour. Today the same plane flew from City A to City B along the same route at an average speed of 450 miles per hour. How many more minutes took the plane to fly yesterday than it took today?
A. 10
B. 15
C. 20
D. 25
E. 30
A. 10
B. 15
C. 20
D. 25
E. 30
03 Jan 2021, 08:20
Kudos
Bookmarks
Bunuel
"it took a certain plane 3 hours to fly from City A to City B at an average speed of 400 miles per hour."
We should immediately deduct the total distance is \(400 mi/h * 3 h = 1200 mi\) upon seeing this. Then the 2nd trip took \(\frac{{1200 mi}}{{450 mi/h}} = 2 + \frac{300}{450} = 2 + \frac{2}{3} = 2 hours 40 min\). Therefore he saved 20 min by driving 50 mi/h faster.
Another interesting way to approach this is to use the ratio method, the distance is fixed so the time and speed have an inverse proportional relation. The speed is multiplied by \(9/8\) in order to go from 400 to 450. Then the time is multiplied by \(\frac{8}{9}\), so \(\frac{1}{9}\) less and \(\frac{1}{9}\) of 3 hours is 20 min.
Ans: C
24 Apr 2022, 01:27
Kudos
Bookmarks
TestPrepUnlimited
Great explanation TestPrepUnlimited. Could you explain how to work out 8/3 is 2 hours 40 min ? Thanks
