Help!! Need Assitence with a Question

Question

So i cam across this question the other day, and I cant figure it out and its bothering me. Im writing this off the top of my head so please forgive me for not remembering the answer choices.

Ann walks from her house to school at 3mph, and immediately walks back without wasting time from her school to her house at 4mph. If the total time she spent walking was 1.2 hours, how far is the school from her house?

Thanks

BrushMyQuant · Answer

Let the distance between house and school be d miles
Time taken to go from house to school = distance/speed = d/3 hours
Time taken to go from school to house = distance/speed = d/4 hours

Total time taken = Time taken to go from house to school + Time taken to go from school to house
1.2 (given) = d/3 + d/4

1.2 = 7d/12

=> d = 2.057 miles

Hope it helps!

EMPOWERgmatRichC · Answer

Hi psavalia,

Did this question come from a credible GMAT source for practice problems? I only ask because the numbers are "weird" (including the correct answer) for GMAT questions of this type on the Official Test. Also, since you didn't include the answer choices, we're forced to "do math" to answer this question, whereas having the answers would have allowed us to TEST THE ANSWERS and find the solution with a less complex set of calculations.

GMAT assassins aren't born, they're made,
Rich

dabral · Answer

Here is a properly written question, see the attached image, that is very similar to the one posted by  psavalia . This question is from the SAT and written by ETS that used to write the GMAT as well.

C

Cheers,
Dabral

EMPOWERgmatRichC · Answer

Hi psavalia,

The question that dabral posted is far more "in line" with how the GMAT would phrase the prompt (including the types of numbers in the prompt and in the answer choices). By having these answers, we can actually use them to our advantage (since one of them MUST be the distance from the base to the top of the mountain).

Given the two Rates and the Total Time...
2 km/hour going up
3 km/hour going down

Total Time = 10 hours

...we can TEST THE ANSWERS.

Let's TEST Answer B = 10 km

IF....
Distance = 10km
Time to go up....
10km = (2km/hr)(T)
5 hours = T

Time to go down...
10km = (3km/hr)(T)
3.333 hours = T

Total Time = 5 + 3.333 = 8.3333 hours
This is TOO SMALL (the Total Time is supposed to be 10 hours).
This means that the Distance needs to be BIGGER (but not that much bigger, since 8.333 is close to 10).

Let's TEST Answer C = 12km

IF....
Distance = 12km
Time to go up...
12km = (2km/hr)(T)
6 hours = T

Time to go down...
12km = (3km/hr)(T)
4 hours = T

Total time = 6 + 4 = 10 hours.
This is a MATCH for what we were told, so C MUST be the answer!

Final Answer:  C

You'll find that most GMAT questions can be approached in a variety of ways, so you have to practice more than one method and keep your eyes open for multiple approaches. Top Test Takers are flexible in their thinking - they use the "clues" available to them (including what's in the Answers) to their advantage and use whatever method is the fastest/easiest to get to the correct answer.

GMAT assassins aren't born, they're made,
Rich

devesh19 · Answer

Hi Guys,

Can you please help me with some of the questions below;

Q1. What is the range of a set consisting of the first 100 multiples of 7 that are greater than 700?

A.693 B.700 C.707 D.777 E. 847

Q2. At a conference with 100 attendees, are there any students of the same age (rounded to nearest year) who attend the same school?

A. The range of ages of the participants is 22-30, inclusive
B. Participants represent 10 business schools

Q3. If a randomly selected non-negative single digit integer is added to set X  , what is the probability that the median of the set will increase while its range will remain the same?
A.20% B.30% C.40% D.50% E.60%

Q4. The GMAT is cored on a scale of 200-800 in 10 points increments. A first year class at a certain business school consists of 478 students. Did any students of the same gender in the first year class who were born in the same named month have the same GMAT score?
A. The range of GMAT scores in the first year class is 600-780
B. 60% of the students in the first year class are male.

It will be fantastic if i can have a quick reply.

Thanks in advance.
Devesh

EMPOWERgmatRichC · Answer

Hi devesh19,

To help keep each thread focused on one question/theme, I highly recommend that you separate these 4 questions into 4 separate posts (and post them in the appropriate Forums - PS and DS). In that way, you'll be able to receive advice/information on each subject individually without having to jumble 4 different conversations in one thread.

GMAT assassins aren't born, they're made,
Rich

Help!! Need Assitence with a Question

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