In recent years traffic congestion has become increasingly severe at t

Question

In recent years traffic congestion has become increasingly severe at the intersection of two busy roads, Province Highway and Central Highway. This intersection lies between Weston and Eastburg on Province Highway and between South City and Northville on Central Highway. A stoplight at the intersection controls traffic flow. The stoplight's signals operate on a repeated cycle with fixed timing, always directing traffic to flow according to the following order (there are brief gaps in time between each of the following to ensure that traffic has cleared the intersection):

1. First, all and only the traffic traveling straight along Province Highway, from both directions
2. Second, all and only the traffic turning left off of Province Highway, from both directions
3. Third, all and only the traffic traveling straight along Central Highway, from both directions
4. Fourth, all and only the traffic turning left off of Central Highway, from both directions
5. Fifth, all and only the traffic turning right off of either highway, in all directions

Highway planners intend to change the timing of the signals for weekdays so that the length of each signal during the cycle is proportional to the number of vehicles passing through the intersection on a typical weekday morning in the directions controlled by that signal.

Manifesting710 · Accepted Answer

I had the most trouble deciphering which is the province highway and which central highway

q1 got it perfect q2 got 2qs right 1 wrong q3 wrong In my opinion, Most of my mistakes were just from not being able to understand what is what

chetan2u · Answer

(I)  Province   HW: West to east;  Central  HW: South to North
Certain rules: P HW straight and then left, followed by P HW straight and then left and finally all right.

(II) Next, stoppage time on signals is given

(III) Finally a chart of traffic flow is given

Let us see the questions. 
 (a) The number of vehicles passing straight through the intersection on Central Highway on a typical weekday morning
Can be calculated from (III) 
(b) The current duration in seconds, including gaps, of one full cycle on the stoplight's signals
(II) clearly states that the timings do not include the gaps. So, the total time including gaps CANNOT be measured.
(c) The percent of the vehicles passing through the intersection on a typical weekday morning that turn left off of Province Highway, from both directions
We can calculate the total vehicles and also the vehicles that turn left off of P HW from (III)

answer Yes, No, Yes

From, (II) we get the 40 seconds signal is for RIGHT turn from both highways, and from (III) we get the numbers turning right as below
North to west: 1000
West to South: 2000
South to East: 2000
East to North: 1250
 1,000 => Yes
2,000 => Yes
3,000 => No

From (II), we get 20 seconds signal is for left turn on P HW.
Now we are concerned with traffic from Weston.
Total vehicles from Weston = 2200(left turn) + 5000(straight) + 2000(Right turn) = 9200
 So % that take a left turn = 2200/9200 = 11/46

chetan2u · Answer

What does one specific direction means?
It means from east or from west and so on.

If it were to mean that the number coming from a direction has to be unique, it could be
1) Number of vehicles unique to a specific direction.

sgpk242 · Answer

chetan2u  I'm still not sure based on your explanation. As you said, from one specific direction means from the east, or from the west, etc. Mathematically, or means one, or the other, but not both. Your counter example with the word "unique" uses "specific direction" in your definition, which is the phrase we're trying to define, so it is still unclear.

chetan2u · Answer

If I write unique from a direction, it means the number of vehicles coming from a direction must be unique.

My stress was on ‘unique’ and that if it were to mean what earlier posts suggested, word similar to unique would be used.

If I write number of vehicles from a specific direction, specific is adjective referring to direction so it talks of east or west etc. 
So, the point on same number of vehicles from a direction not to be considered is not mentioned anywhere.

KarishmaB · Answer

Note that we have been given figures for each direction and each turn. For example, look at the lightest grey bar of people coming from Weston. 5000 came straight, 2000 turned right and 2200 turned left. Similarly we have all figures for all other towns too.

Question 1.

For each of the following quantities, select Yes if it can be deduced from the information provided. Otherwise, select No.

The number of vehicles passing straight through the intersection on Central Highway on a typical weekday morning

Central highway is the vertical one. We have figures for people going from North to South (3000) and South to North (5000). Hence this can be deduced from the give info. 
 ANSWER: YES

The current duration in seconds, including gaps, of one full cycle on the stoplight's signals

We do not know the duration of "gaps". Signal times do not include gaps. Note in the second tab "The gaps in time between each step in the pattern are not included in the times given below." Hence we cannot deduce this. 
 ANSWER: NO

The percent of the vehicles passing through the intersection on a typical weekday morning that turn left off of Province Highway, from both directions

We have all the values so we can find how many people are turning left off Province highway. So we can simply mark Yes and move on without actually looking for the values (2200 coming from West and 3000 coming from East. We will need to divide this by the total number of vehincles, a calculation which will take time and should not be done)
 ANSWER: YES

Question 2.

For each of the following numbers, select Yes if it is the number of vehicles passing through the intersection from one specific direction during the current 40-second signals on a typical weekday morning, according to the information provided.
Otherwise, select No.

40 second signals are at all right turns. 
From East - 1240 turn right. From North - 1000 turn right. From West - 2000 turn right and From South - 2000 turn right

1000 -  YES

2000 -  YES

3000 -  NO 
 ANSWER

Question 3.

Based on the information provided, what fraction of the number of vehicles on typical weekday mornings, passing through the intersection from Weston, passes through the intersection during the current 20-second-long stoplight signals?

20 sec signals are the left turns from Province. (2200 coming from West)
Also from Weston, 5000 go straight and 2000 go right. 
Hence required fraction =  \frac{2200}{(2200 + 5000 + 2000)} = \frac{22}{92} = \frac{11}{46}

ANSWER: 11/46

Dj06 · Answer

can somebody clearify if this is an actual gmat level question being asked in focus edition. Questions were not difficult but diagram is a complete mess.

Bunuel · Answer

Yes, this is a GMAT Prep official mock question.

Bismuth83 · Answer

1. First, we can draw out the names on the highway intersection:

2. Part 1. We are asked to figure out whether we can answer the statements or not.

The number of vehicles passing straight through the intersection on Central Highway on a typical weekday morning. This will be equal to 3,000 + 5,000 = 8,000 vehicles. So, this statement can be answered.
The current duration in seconds, including gaps, of one full cycle on the stoplight's signals. Here, the problem is that the duration of a gap is unknown. So, this statement cannot be determined.

The percent of the vehicles passing through the intersection on a typical weekday morning that turn left off of Province Highway, from both directions. This will be equal to \(\frac{2,200 + 3,000}{690 + 5,000 + 1,000 + 2,200 + 5,000 + 1,240 + 2,400 + 5,000 + 2,000 + 3,000 + 3,000 + 2,000} = \frac{520}{3253} \approx 16\)%. So, this statement can be answered.

3. Part 2. We are asked to select which numbers match the number of vehicles from any specific direction that go during a 40-second signal. From the table, we know that this happens when a vehicle turns right at any highway and direction. So, there are 4 possible numbers:

1,000 works, 2,000 works, and 3,000 isn't here.

4. Part 3. We have to find the fraction of vehicles that pass through the intersection from Weston that do it under a 20-second stop-light. From the table, it's known that this happens only under a left turn from Province highway.

The number of vehicles that do this are 2,200. So, the fraction will be \(\frac{2,200}{2,200 + 5,000 + 2,000} = \frac{2200}{9200} = \frac{22}{92} = \frac{11}{46}\). So, our answer will be \(\frac{11}{46}\).

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anushkatew · Answer

is this really 555-605 level? took me a decent amount of time to decode the figure but the questions are straight forward - trying to understand if I can skip such a question on my test.

cheshire · Answer

Most MSR questions are easy to answer after you've decoded the information as that's the hard and time consuming part. If you come across a question that's not hard and you can confidently say will take over 5 minutes, I'd consider skipping it for questions you think can answer more quickly or accurately, as it will likely net you more points in a shorter amount of time.

anushkatew

is this really 555-605 level? took me a decent amount of time to decode the figure but the questions are straight forward - trying to understand if I can skip such a question on my test.

anushree01 · Answer

We have all the values so we can find how many people are turning left off Province highway. So we can simply mark Yes and move on without actually looking for the values (2200 coming from West and 3000 coming from East. We will need to divide this by the total number of vehincles, a calculation which will take time and should not be done)
ANSWER: YES

dhruvgupta2 · Answer

is this an actually 605 level question , I find it to be an 705 minimum ques

Bunuel · Answer

The difficulty level of a question on the site, after sufficient attempts, is determined  automatically  based on various parameters collected from users' attempts via timer, such as the percentage of correct answers and the time taken to answer the question. So, this is an 555-605 level question based on our statistics.

GMATCoachBen · Answer

dhruvgupta2

I also found it harder than most questions when I first did it, because the diagram is so unusual.

It can be very helpful to take a deep belly breath to calm any initial anxious reaction, so you can focus better, and then go step by step. We need to make sense of the diagram, and then it's not as bad.

Also note that although the test is adaptive, it will gave you a wide range of difficulties throughout the section. You will see a lot of medium questions even when you are scoring very high.

For example, on the official practice test shown below, I scored a perfect DI 90, but I still got 2 easy, 9 medium, and 9 hard questions.

And on my Q 88, the average question difficulty was a 645, and only 4 questions were rated above 700.

dhruvgupta2

is this an actually 605 level question , I find it to be an 705 minimum ques

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avellanjc · Answer

Chetan,

For the last question (3rd one)... When considering the fraction of the traffic that passes through the 20 sec stoplight, shouldnt one take into account the partial amounts that passes in all directions? Also, shouldn't one consider the order of flow given in the 1st tab(First flows straight traffic, the left, etc etc?

What I mean with partial amount of traffic Is the following: In the straight traffic in Province Highway From Weston To Eastbourg in a 20 second "green light" wouldn't   cars pass through the light?

I am aware that the correct answer only takes into account the turn left traffic in Province Highway (weston to eastbourg direction) because the 20 sec stoplight coincides with the 20 second stoplight in the question prompt. Yet all the questions above, remain bugging in my mind.

Regards,

Juan C. Avelan

shaliny · Answer

KarishmaB 
 GMATCoachBen

here how would i know that in Q3 while taking 20 s vehicle only from weston vehicle on PH be including ? why 3000 Vehicles turning left in 20 sec on Ph are not included in solving fraction?

KarishmaB · Answer

The question says:

...  what fraction of the number of vehicles on typical weekday mornings, passing through the intersection  from Weston , passes through the intersection during the current 20-second-long stoplight signals?

This means we are to consider the vehicles passing through the intersection coming FROM WESTON only. FROM Weston, only 2200 vehicles are taking left.

	\(\frac{23}{233}\)
	\(\frac{5}{23}\)
	\(\frac{11}{46}\)
	\(\frac{55}{211}\)
	\(\frac{25}{72}\)

In recent years traffic congestion has become increasingly severe at t

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GMAT Multi-Source Reasoning (MSR) Questions

In recent years traffic congestion has become increasingly severe at t

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