If Juan takes 11 seconds to run Y yards. How many seconds w

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susanring: Newbie | Next Rank: 10 Posts; Posts: 2; Joined: Sun Nov 02, 2008 7:15 pm

by susanring » Sun Nov 02, 2008 7:18 pm

If Juan takes 11 seconds to run Y yards.
How many seconds will it take him to run x yards at the same rate?

Answer:
11x/y

I understand that D = R * T
Questions
Why is the rate = y/11 and not 11 over Y since, If Juan takes 11 seconds to run Y yards.

Why is the equation
X= y/11 *t

Can someone walk me through?
These word problems are confusing?

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Mani_mba: Master | Next Rank: 500 Posts; Posts: 267; Joined: Wed Jul 16, 2008 12:20 amFollowed by: 1 member; Thanked: 4 times

by Mani_mba » Sun Nov 02, 2008 7:34 pm

I think you almost got it ..
This is my approach:
------------------------
Juan takes 11 seconds to run y yards .
He would take 11/y seconds to run 1 yard.

So for x yards, he would take x(11/y).

In your approach:
---------------------
D = RT
y = (R) 11
R = y/11

For x yards:

x = (R) t
t = x/R = 11x/y.

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earth@work: Master | Next Rank: 500 Posts; Posts: 248; Joined: Mon Aug 11, 2008 9:51 am; Thanked: 13 times

by earth@work » Sun Nov 02, 2008 7:43 pm

D = R * T; R=D/T
now, equation X= y/11 *t
x=(y/11)*t
x=(old distance=y)/(old time=11sec) *t
which is correct as (old distance/old time)=constant speed,R
New Distance(=x) =R*t

hope this clears ur doubt

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raunekk: Legendary Member; Posts: 1159; Joined: Wed Apr 16, 2008 10:35 pm; Thanked: 56 times

by raunekk » Sun Nov 02, 2008 9:51 pm

rate= distance / time

hence rate=y yards/ 11 secs

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Jeff@TargetTestPrep: GMAT Instructor; Posts: 1462; Joined: Thu Apr 09, 2015 9:34 amFollowed by: 22 members; Location: New York, NY; Thanked: 39 times

by Jeff@TargetTestPrep » Tue Apr 21, 2015 1:23 pm

susanring wrote:If Juan takes 11 seconds to run Y yards.
How many seconds will it take him to run x yards at the same rate?

Answer:
11x/y

I understand that D = R * T
Questions
Why is the rate = y/11 and not 11 over Y since, If Juan takes 11 seconds to run Y yards.

Why is the equation
X= y/11 *t

Can someone walk me through?
These word problems are confusing?

If Juan takes 11 seconds to run y yards, how many seconds will it take him to run x yards at the same rate?

(A) 11x/y
(B) 11y/x
(C) x/(11y)
(D) 11/(xy)
(E) xy/11

Solution:

This problem is testing us on the Rate x Time = Distance relationship. This relationship also tells us that Rate = Distance/Time and Time = Distance/Rate.

Ultimately, we are looking for how many seconds it will take Juan to run x yards. Thus, the equation we'll use is: Time = Distance/Rate. We know the distance is x yards, and we need to find Juan's rate.

We can find Juan's rate as follows: Rate = Distance/Time = y yards/11 seconds

Using that rate, we need to determine how long it takes him to run x yards at the same rate. So we have:

Time = Distance/Rate

Time = x yards/(y yards/11 seconds)

Time = (x yards) x (11 seconds/y yards)

Time = 11x/y seconds

The answer is A

Jeffrey Miller
Head of GMAT Instruction
[email protected]

See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews

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[email protected]: Elite Legendary Member; Posts: 10392; Joined: Sun Jun 23, 2013 6:38 pmFollowed by: 511 members; Location: Palo Alto, CA; Thanked: 2867 times; GMAT Score:800

by [email protected] » Tue Apr 21, 2015 8:13 pm

Hi All,

While the original post is quite old, there are a couple of lessons that can be taken from this prompt:

1) Be sure to INCLUDE the answer choices. By not including the answers, the original poster is forced (and forces us) to approach this question in one general way: with algebra. Most questions on Test Day can be approached in a variety of different ways IF you consider how the answer choices are written.

2) This question is actually perfect for TESTing VALUES. Since Jeff has included the answer choices with his post, we can properly TEST VALUES.

We're told that it takes Juan 11 seconds to run Y yards. We're asked how many seconds it takes him to run X yards at that same rate.

IF....
Y = 2
X = 4
We know that Juan takes 11 seconds to run 2 yards. At that same rate, he would need 22 seconds to run 4 yards. So we're looking for an answer that = 22 when Y = 2 and X = 4...

Answer A: 11X/Y = 44/2 = 22 This IS a match
Answer B: 11Y/X = 22/4 NOT a match
Answer C: X/(11Y) = 2/44 NOT a match
Answer D: 11/(XY) = 11/8 NOT a match
Answer E: (XY)/11 = 8/11 NOT a match

Final Answer: A

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

Contact Rich at [email protected]

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