A cyclist leaves A at 10 am and reaches B at 11 am. Starting from 10:0

Question

A cyclist leaves A at 10 am and reaches B at 11 am. Starting from 10:01 am, every minute a motor cycle leaves A and moves towards B. Forty-five such motor cycles reach B by 11 am. All motor cycles have the same speed. If the cyclist had doubled his speed, how many motor cycles would have reached B by the time the cyclist reached B?

A. 23
B. 22
C. 21
D. 20
E. 15

Are You Up For the Challenge: 700 Level Questions

A. 23
B. 22
C. 21
D. 20
E. 15

Are You Up For the Challenge: 700 Level Questions

GMATinsight · Accepted Answer

45 Motor cyclist reach B by 11

First motor cyclist started at 10:01
i.e. 45th motor cyclist started at 10:45 and reached at 11 AM   i.e. Motor cyclist takes 15 minutes to reach from A to B

If the Cyclist doubled the speed then he will reach B at 10:30 instead of 11

i.e. Last motor cyclist who reaches at 10:30 must have started 15 minutes ago i.e. @10:15 AM

So total Motor cyclist who would have reached B by the time the cyclist reached B = 15 (starting from 10:01 to 10:15]

Answer: Option E

gurmukh · Answer

Doubling the speed cyclist will reach B at 10:30 am. 
Now motor cyclist start at 10:01 and every minute one motor cyclist leaves for B. Hence the one starting at 10:45 also reached B till 11 am.
Similarly half an hour early the motor cyclist which started at 10:15 will be able to reach till 10:30 
So 15 is the answer
IMO choice E is the answer

chetan2u · Answer

So, 45 motorcycles reach at B at gap of one minute each, so the first reached at : 1100hrs - 0045 = 1015.

The  cyclist by doubling will reach in half the time , so he reaches by 1030..
Motorcyclists at B by 1030 = 1030-1015=15

E

GMATWhizTeam · Answer

Solution:  
 • The cyclist took 1 hr to reach point B.
 o Starting from 10:01 am, every minute a motorcycle leaves point A and move towards B.
o Till 11: 00 am 45 such motorcycles reached point B.
  45th motorcycle must have left point A at exactly 10:45 am to reach point B at 11:00 am
 Time taken by motorcycle to cover the distance AB = 15min. 
o Now, the speed of cyclist is doubled.
  Cyclist will reach point B at 10: 30 am 
o The last motorcycle must leave point A, 15 minutes before 10: 30 am.
  The last motorcycle will leave point A exactly at 10: 15 am to reach point B at exactly 10: 30 am. 
o The number of motorcycles reached point B until 10:30 am = 15.
  Starting from 10:01 am, every minute a motorcycle left point A till 10: 15 am   
Hence, the correct answer is  Option E.

Kinshook · Answer

Given:
1. A cyclist leaves A at 10 am and reaches B at 11 am.
2. Starting from 10:01 am, every minute a motor cycle leaves A and moves towards B. Forty-five such motor cycles reach B by 11 am.
3. All motor cycles have the same speed.

Asked: If the cyclist had doubled his speed, how many motor cycles would have reached B by the time the cyclist reached B?

Last motorcycle starting at 10:45 am reaches B.
Motorcycles take 15 mins to travel from A to B.

Cyclist takes 1 hour = 60 mins to travel from A to B.
If he doubles the speed.
Cyclist will take 30 mins to travel from A to B.

Last motorcycle to reach from A to B will start at 10:15 am

Total 15 motor cycles would have reached B by the time the cyclist reached B.

IMO E

ScottTargetTestPrep · Answer

Since 45 motorcycles reach B by 11 am, it means the last motorcycle to leave A is at 10:45 am (and still arrives B at 11 am). So it takes this motorcycle or any motorcycle 15 minutes to cover the distance between A and B. We are given that the cyclist takes 1 hour to cover the same distance. However, if his speed doubles, then it would only take him 30 minutes to cover that distance. In other words, he will reach B at 10:30 am. Since it would still take 15 minutes for any motorcycle to travel from A to B, there will be only 15 motorcycles reaching B by 10:30 am (with the last one leaving at 10:15 am).

Answer: E

lavanya.18 · Answer

TRICKY QUESTION!!

45 MC reach B by 11

1st MC left at 10:01
The last MC must have left at 10:45 to reach 11:00, Which means it takes MC 15 minutes to reach B from A.

If the cyclist 2x his speed, he reaches b at 10:30.
For this last MC would have to reach by 10:30 too.
It takes MC 15 min, so to reach 10:30, he must have left at 10:15.

From 10:01 to 10:15, 15 MC left A to reach B

ANS: 15 that is E

ClaireCHEN · Answer

A cyclist leaves A at 10 am and reaches B at 11 am. Starting from 10:01 am, every minute a motor cycle leaves A and moves towards B. Forty-five such motor cycles reach B by 11 am. All motor cycles have the same speed. If the cyclist had doubled his speed, how many motor cycles would have reached B by the time the cyclist reached B?

let's assume A-B is 1km, it means cyclist's speed is 1km/h, since 45 motor cycles finished 1km means the motor departed at 10:45 drove exactly 1km, motor cycle's speed is 4km/h (1km/15mins).
If cyclist doubled his speed up to 2km/h, it took him 30mins to arrive at B, then set the departure time of which is the last motor in the queue that passed 1km at 10:30 as 10:xx, then 10:30-10

x= the time duration for a motor cycle to finish 1km, then it's 10:15, then 15 in ttl motor cycles.

x= the time duration for a motor cycle to finish 1km , then it's 10:15, then 15 in ttl motor cycles.

HamP95 · Answer

This is a challenging question because it requires word problem comprehension along with a distance problem where the information provided to solve the problem is not "obvious". Lets go through it.

Firstly, we know that every minute, starting at 59 minutes before the cyclist arrives at B, 1 motorcycle leaves.
We are also told that 45 motorcycles reach B by 11am, and all have the same speed

If 1 leaves every minute, at the same speed, the 45th motorcyclist will have left at 10:45 AM (10:01 first leaves, 10:02 second leaves, so 45th leaves at 10:45)

Therefore, the motorcycles take 11 - 10:45 to go from A to B = 15 mins

If the cyclist doubled his speed, if it took him from 10 to 11am originally or 60 minutes, it would take him 60/2 minutes, or 30 minutes, to arrive at B, so he would arrive at 10am + 30 mins = 10:30

If the motorcycles go the same speed and take 15 mins to arrive, the last one to make it to B would've left at 10:30 - 15 mins = 10:15, or the 15th motorcycle to leave (knowing they leave every minute on the minute)

Answer: E, 15.

nikitathegreat · Answer

But how do we know that he (a person who started at 10:45) exactly reached at 11:00AM. We are told 45 motorcyclists reaches by 11AM. So what if guy who started at 10:45 reaches by 10:50 i.e 5 mins ?? This got me confused and hence I couldn't calculate the exact people who reached by 10:30AM.

A cyclist leaves A at 10 am and reaches B at 11 am. Starting from 10:0

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards

GMAT Problem Solving (PS) Questions

A cyclist leaves A at 10 am and reaches B at 11 am. Starting from 10:0

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards