VICS Problem -- Need Help

[joostinshu]

Bob bikes to school every day at a steady rate of x miles per hour. On a particular day, Bob had a flat tire exactly halfway to school. He immediately started walking to school at a steady pace of y miles per hour. He arrived at school exactly t hours after leaving his home. How many miles is it from the school to Bob's home?


(x + y) / t


2(x + t) / xy


2xyt / (x + y)


2(x + y + t) / xy


x(y + t) + y(x + t




I need someone to clearly explain this.... I was able to solve it a week ago and am a little bummed that I can no longer solve.

[ssmiles08]

I got 2xyt / (x + y) as my answer

lets say d as the total number of miles to set up a chart

rate / dist.---> time

x / d/2----> time will then be dist/rate (d/2x)

y / d/2----> time will be dist/rate (d/2y)


So in entirety it takes t time to complete the whole distance d.

so you can add the times: (d/2x) +(d/2y) = t and solve for d.

(2yd+2xd)/ 4xy = t

4xyt = 2d(x+y)

2xyt = d(x+y)

2xyt/(x+y)

Does this match the OA?

[joostinshu]

It absolutely does match. I actually figured the problem out shortly after posting. The key is getting a common denominator when solving for t for the 1st 1/2 and the 2nd 1/2 of the trip. Then it is just manipulating the equation to solve for D.

Thanks for responding!

[skang357]

Hey isn't this problem off an MGMAT cat?

Doesn't it show how to do it there?

[joostinshu]

It does provide the answer solution but when you are the night before the exam and have used 14 Manhattan practice exams, going back to find that given problem takes time.

Thanks for the help.

[bumblenbumble01]

I got 2xyt / (x + y) as my answer

lets say d as the total number of miles to set up a chart

rate / dist.---> time

x / d/2----> time will then be dist/rate (d/2x)

y / d/2----> time will be dist/rate (d/2y)


So in entirety it takes t time to complete the whole distance d.

so you can add the times: (d/2x) +(d/2y) = t and solve for d.

(2yd+2xd)/ 4xy = t

4xyt = 2d(x+y)

2xyt = d(x+y)

2xyt/(x+y)

Does this match the OA?

het there, looks like i'm missing something here. if time=r/d why and how do you use d/r = time in the first part of the problem?

[ssmiles08]

het there, looks like i'm missing something here. if time=r/d why and how do you use d/r = time in the first part of the problem?

Sorry I made a typo(but the calculations are right)...time is always distance / rate.


rate = x
distance for the first half = d/2

distance over rate = (d/2) / (x) = d/(2x)---> time for the fist half

rate = y
distance for the second half = d/2

distance over rate = (d/2) / (y) = d/2y---> time for the second half

time for the first half + time for the second half = total time

(d/2x) +(d/2y) = t

solve for d; d = 2xyt/(x+y)

[doclkk]

Answer is C for sure.

[lunarpower]

It does provide the answer solution but when you are the night before the exam and have used 14 Manhattan practice exams, going back to find that given problem takes time.

Thanks for the help.

hi -

did you know that you can go back and review the problems by topic? if you do so, then it shouldn't take you long to find the problem. (certainly not as long as it takes you to post a thread here.)

here's what you do:

* go to "generate assessment reports" from your exams home page
* select all of the exams that may possibly have contained this question (you probably remember the rough time frame in which you saw it).
* once the assessment reports are on-screen, select "quant by subject / topic area" (this should be the second link from the bottom, if i remember correctly)
* click on "algebra" on top
* go to "VIC" and click on it

there shouldn't be that many problems. go through them one by one until you've found the one you're looking for. (the title should probably give it away; if not, click on them one by one.)

--

you've seriously taken 14 of our practice exams? as in, you've reset the exams twice already?

are you sure you're reviewing the problems thoroughly enough for TAKEAWAYS?
(see here: https://www.beatthegmat.com/gmat-prep-pl ... html#52813)

that's a LOT of exams. unless you've been at this for a very, very, very long time, you may want to spend less time taking practice tests and more time reviewing the tests you've already taken.