|
|
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.
02 Nov 2019, 02:10
Kudos
Bookmarks
B
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
95%
(hard)
Question Stats:
39% (02:51) correct
61%
(02:56)
wrong
based on 145
sessions
History
Date
Time
Result
Not Attempted Yet
Two persons A and B start from the opposite ends of a 450 km straight track and run to and from between the two ends. The speed of the first person is 25 m/s and the speed of other is 35 m/s. They continue their motion for 10 hours. How many times did they pass each other?
A. 1
B. 2
C. 3
D. 4
E. 5
A. 1
B. 2
C. 3
D. 4
E. 5
02 Nov 2019, 03:43
Kudos
Bookmarks
jackfr2
Let us find the total distance traveled by both combined.
Combined speed = (25+35) or 60 m/s, which is same as \(\frac{60m}{\frac{hr}{60*60}}=\frac{60*60*60m}{hr}\) or 216kmph =>
In 10 hrs they will travel 216*10=2160km @ 216kmph.
The first time both meet, they cover a combined distance of 450km, that is 1 lap,
But next time they meet both cover a distance of 900km, that is they cover 2 laps.
Next they should meet after another 900kms or 450+900+900=2250, but they have traveled only 2160 in 10 hrs, so they do not meet 3rd time in 10 hrs.
Answer 2 times
B
General Discussion
02 Nov 2019, 03:41
Kudos
Bookmarks
speed of first person=\(25*(\frac{18}{5})\)=90 kmph
speed of second person=\(35*(\frac{18}{5})\)=126 kmph
Time taken by them to meet first time= \(\frac{450}{216}\)= 2.x hours
Time taken by them to meet second time= \(2.x+(\frac{2*450}{216})\)=6.y hours
Time taken by them to meet third time= \(6.y+(\frac{2*450}{216})\)= 10.z hours >10
Hence, they passed each other 2 times.
speed of second person=\(35*(\frac{18}{5})\)=126 kmph
Time taken by them to meet first time= \(\frac{450}{216}\)= 2.x hours
Time taken by them to meet second time= \(2.x+(\frac{2*450}{216})\)=6.y hours
Time taken by them to meet third time= \(6.y+(\frac{2*450}{216})\)= 10.z hours >10
Hence, they passed each other 2 times.
jackfr2
