Events & Promotions
|
|
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.
Nov 2211:00 AM IST
-01:00 PM IST
Do RC/MSR passages scare you? e-GMAT is conducting a masterclass to help you learn – Learn effective reading strategies Tackle difficult RC & MSR with confidence Excel in timed test environment- Nov 23
11:00 AM IST
-01:00 PM IST
Attend this free GMAT Algebra Webinar and learn how to master the most challenging Inequalities and Absolute Value problems with ease. 
Nov 2510:00 AM EST
-11:00 AM EST
Prefer video-based learning? The Target Test Prep OnDemand course is a one-of-a-kind video masterclass featuring 400 hours of lecture-style teaching by Scott Woodbury-Stewart, founder of Target Test Prep and one of the most accomplished GMAT instructors.
06 Dec 2020, 07:21
Kudos
Bookmarks
before meeting point
let the time traveled by both a & b till meeting point is T mins
Let speed A = a, distance travelled by A in T mins = a*T
let speed B = b, distance travelled by B in T mins = b*T
after meeting point
A reached NY in 40 min at speed 'a':- distance = time * speed = 40*a
B reached Boston in 90 mins at speed 'b':- Distance = 90*b
distance travelled by A after meeting point = distance travelled by B before meeting point
therefore
b*T = 40*a.....................(1)
similarly a*T = 90*b.........(2)
multiply (1) and (2)
a*T * b*T = 40*a*90*b
T=sqrt (40*90)= 60 mins
total time by A= 60+40 = 100 mins
let the time traveled by both a & b till meeting point is T mins
Let speed A = a, distance travelled by A in T mins = a*T
let speed B = b, distance travelled by B in T mins = b*T
after meeting point
A reached NY in 40 min at speed 'a':- distance = time * speed = 40*a
B reached Boston in 90 mins at speed 'b':- Distance = 90*b
distance travelled by A after meeting point = distance travelled by B before meeting point
therefore
b*T = 40*a.....................(1)
similarly a*T = 90*b.........(2)
multiply (1) and (2)
a*T * b*T = 40*a*90*b
T=sqrt (40*90)= 60 mins
total time by A= 60+40 = 100 mins
09 Mar 2022, 09:21
Kudos
Bookmarks
Given: Two cars A and B start from Boston and New York respectively simultaneously and travel towards each other at constant speeds along the same route. After meeting at a point between Boston and New York the two cars A and B proceed to their respective destinations of New York and Boston. Car A reaches New York 40 minutes after the two cars have met and Car B reaches Boston 90 minutes after they have met.
Asked: How long did Car A take to cover the distance between Boston and New York?
Let the speeds of car A & car B be vA & vB respectively and distance from New York to Boston be D.
At the time of meeting: -
Distance covered by car A = vA*D/(vA+vB)
Distance covered by car B = vB*D/(vA+vB)
Distance to be covered by car A = vB*D/(vA+vB)
Time taken by car A to cover the distance = (vB/vA)*D/(vA + vB) = 40 minutes
Distance to be covered by car A = vA*D/(vA+vB)
Time taken by car A to cover the distance = (vA/vB)*D/(vA + vB) = 90 minutes
(vB/vA)^2 = 40/90 = 4/9
vB/vA = 2/3
vA = 3(vA+vB)/5
vB = 2(vA+vB)/5
(vB/vA)*D/(vA + vB) = 40 = (2/5)(D/vA) = 40 minutes
D/vA = 40*5/2 = 100 minutes
Time taken by car A to cover the distance from New York to Boston = D/vA = 100 minutes = 1 hour 40 minutes
IMO D
Asked: How long did Car A take to cover the distance between Boston and New York?
Let the speeds of car A & car B be vA & vB respectively and distance from New York to Boston be D.
At the time of meeting: -
Distance covered by car A = vA*D/(vA+vB)
Distance covered by car B = vB*D/(vA+vB)
Distance to be covered by car A = vB*D/(vA+vB)
Time taken by car A to cover the distance = (vB/vA)*D/(vA + vB) = 40 minutes
Distance to be covered by car A = vA*D/(vA+vB)
Time taken by car A to cover the distance = (vA/vB)*D/(vA + vB) = 90 minutes
(vB/vA)^2 = 40/90 = 4/9
vB/vA = 2/3
vA = 3(vA+vB)/5
vB = 2(vA+vB)/5
(vB/vA)*D/(vA + vB) = 40 = (2/5)(D/vA) = 40 minutes
D/vA = 40*5/2 = 100 minutes
Time taken by car A to cover the distance from New York to Boston = D/vA = 100 minutes = 1 hour 40 minutes
IMO D
16 Aug 2022, 07:45
Kudos
Bookmarks
Hey, looking at the answers provided, they are very helpful, but also quite technical. The approach I figured out to hack my way through the problem is:
1- We know they start at the same time and Car A then gets before to NY. So Car A is FASTER. This, in turn, implies the meeting point is closer to NY than to Boston.
2 - Since the meeting point is closer to NY, we have that 40min+40min<CAR A total journey< 40 min + 90 min. 1h20<CAR A total journey<2h10. This is the case since 2.1. The meeting point is further from Boston, so at least it took Car A 40 min to do Boston - Meeting Point & 2.2. Car A could not have taken longer than Car B to do Boston - Meeting Point.
ONLY possible answer is D. NO further computations required, just logic!
1- We know they start at the same time and Car A then gets before to NY. So Car A is FASTER. This, in turn, implies the meeting point is closer to NY than to Boston.
2 - Since the meeting point is closer to NY, we have that 40min+40min<CAR A total journey< 40 min + 90 min. 1h20<CAR A total journey<2h10. This is the case since 2.1. The meeting point is further from Boston, so at least it took Car A 40 min to do Boston - Meeting Point & 2.2. Car A could not have taken longer than Car B to do Boston - Meeting Point.
ONLY possible answer is D. NO further computations required, just logic!
Bluelagoon
