|
|
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.
09 Jan 2020, 03:11
Kudos
Bookmarks
B
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:
73% (02:39) correct
27%
(03:03)
wrong
based on 164
sessions
History
Date
Time
Result
Not Attempted Yet
Navjivan Express from Ahmedabad to Chennai leaves Ahmedabad at 6 : 30 am and travels at 50 km per hour towards Baroda situated 100 km away. At 7 : 00 am Howrah-Ahmedabad Express leaves Baroda towards Ahmedabad and travels at 40 km per hour. At 7 : 30 Mr. Shah, the traffic controller at Baroda realises that both the trains are running on the same track. How much time does he have to avert a head-on collision between the two trains?
(A) 15 minutes
(B) 20 minutes
(C) 25 minutes
(D) 30 minutes
(E) 35 minutes
(A) 15 minutes
(B) 20 minutes
(C) 25 minutes
(D) 30 minutes
(E) 35 minutes
09 Jan 2020, 03:45
Kudos
Bookmarks
Bunuel
Explanation:
Ahmedabad ---------------100 km ----------Baroda
(Navjeevan express ) ----------------- (Howrah- Ahmedabad)
Leaves at 6.30 am from Ahmedabad ----------------- Leaves at 7.00 am from Baroda
speed=50 kmph ----------------- speed=40 kmph
Traffic controller realizes about the problem at 7.30. First, find the distance travelled by both train till 7.30
distance travelled by Navjeevan express till 7.30= 1*50 = 50km
distance travelled by Howrah Ahmedabad till 7.30= 1/2*40 =20 km
As both trains moving towards each other, remaining distance= 100km- (50+20) = 30 km
relative speed=(50+40) =90 kmph
Time remaining to avert a head-on collision= 30/90=1/3 h= 20 min
IMO-B
General Discussion
05 Aug 2021, 01:31
Kudos
Bookmarks
Solution:
We are given that a train leaves Ahmedabad at \(6:30am\) with \(50kmph\) speed and a train leave Baroda at \(7:00am\) with \(40kmph\) speed.
We are asked in how much time from \(7:30am\) will both the train collide if they are approaching each other.
At \(7:30 am\), train from Ahmedabad moved for 1 hour. Distance \(= speed\times time = 50\times 1 = 50km\)
At \(7:30 am\), train from Baroda moved for 0.5 hour. Distance \(= speed\times time = 40\times 0.5 = 20km\)
Distance between both the trains at \(7:30am = 100-50-20=30km\).
train.png [ 6.42 KiB | Viewed 13727 times ]
Now time for both the trains to collide \(= \frac{distance}{(S_1+S_2)}=\frac{30}{(50+40)} = \frac{30}{90} = \frac{1}{3} hours\)
We know: \(\frac{1}{3} hours = \frac{1}{3} \times 60 = 20 mins\).
Hence the right answer is Option B.
We are given that a train leaves Ahmedabad at \(6:30am\) with \(50kmph\) speed and a train leave Baroda at \(7:00am\) with \(40kmph\) speed.
We are asked in how much time from \(7:30am\) will both the train collide if they are approaching each other.
At \(7:30 am\), train from Ahmedabad moved for 1 hour. Distance \(= speed\times time = 50\times 1 = 50km\)
At \(7:30 am\), train from Baroda moved for 0.5 hour. Distance \(= speed\times time = 40\times 0.5 = 20km\)
Distance between both the trains at \(7:30am = 100-50-20=30km\).
Attachment:
train.png [ 6.42 KiB | Viewed 13727 times ]
Now time for both the trains to collide \(= \frac{distance}{(S_1+S_2)}=\frac{30}{(50+40)} = \frac{30}{90} = \frac{1}{3} hours\)
We know: \(\frac{1}{3} hours = \frac{1}{3} \times 60 = 20 mins\).
Hence the right answer is Option B.
