Last visit was: 18 Nov 2025, 18:42 It is currently 18 Nov 2025, 18:42
Close
GMAT Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Close
Request Expert Reply
Confirm Cancel
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 18 Nov 2025
Posts: 105,355
Own Kudos:
Given Kudos: 99,964
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 105,355
Kudos: 778,078
 [19]
2
Kudos
Add Kudos
17
Bookmarks
Bookmark this Post
Most Helpful Reply
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 18 Nov 2025
Posts: 105,355
Own Kudos:
Given Kudos: 99,964
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 105,355
Kudos: 778,078
Kudos
Add Kudos
Bookmarks
Bookmark this Post
General Discussion
User avatar
Gmatfox
Joined: 09 Jan 2015
Last visit: 17 Nov 2025
Posts: 11
Own Kudos:
34
 [4]
Given Kudos: 6
Posts: 11
Kudos: 34
 [4]
3
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
User avatar
imeanup
Joined: 15 Jun 2017
Last visit: 17 Sep 2025
Posts: 452
Own Kudos:
607
 [1]
Given Kudos: 8
Location: India
Posts: 452
Kudos: 607
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
My approach would be as follows;
First I will find the opposite \(\angle\) between the height and base of the green pole. \(tan x = \frac{1}{2}\)
This could be used in the red pole;

\(\frac{6}{x} = \frac{1}{2} = tan x \)

\(x=12\)

Now consider another triangle with x and (12-4) as a side with the same angle extended.

\(\frac{x}{8 }= \frac{1}{2} \)

\(x= 4\)

Ans E
User avatar
Sumi1010
Joined: 21 Aug 2018
Last visit: 19 Jan 2025
Posts: 300
Own Kudos:
696
 [1]
Given Kudos: 20
Location: India
Posts: 300
Kudos: 696
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
The light source is placed in such a way that the shadow of the vertical bars get elongated to double.

If there were no wall, the shadow of the red bar would have been 6x2 = 12 units on the floor.
Of the 12 units, 4 units are on the floor, but remaining units fall on the wall. The equivalent of 8 units length (that would have been on floor) is 4 units length (length on wall = half of the length on floor .

E
User avatar
shyam30
Joined: 20 Feb 2019
Last visit: 26 Aug 2021
Posts: 4
Own Kudos:
10
 [1]
Given Kudos: 95
Location: Viet Nam
Concentration: Social Entrepreneurship, Nonprofit
GPA: 2
Posts: 4
Kudos: 10
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Going for option E.


Attachments

Solution.png
Solution.png [ 18.24 KiB | Viewed 4479 times ]

User avatar
Kinshook
User avatar
Major Poster
Joined: 03 Jun 2019
Last visit: 18 Nov 2025
Posts: 5,793
Own Kudos:
5,509
 [1]
Given Kudos: 161
Location: India
GMAT 1: 690 Q50 V34
WE:Engineering (Transportation)
Products:
GMAT 1: 690 Q50 V34
Posts: 5,793
Kudos: 5,509
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Given: In the image above, the green bar has a height of 1 and casts a shadow of 2 on the floor and the red bar has a height of 6 and casts a shadow of 4 on the floor which continues to a height of x on a parallel to the bars wall.
Asked: What is the value of x? (Assume that the light source is distant, the floors and walls are perfectly flat, and the floor is perpendicular to the bars and walls)

Shadow of height 1 is 2 on the floor and 1 on the wall.
Since shadow of 4 is on the floor, height of 2 is consumed and balance 4 (6-2) will be shown on the wall.

IMO E
Attachments

2.png
2.png [ 11.36 KiB | Viewed 2895 times ]

User avatar
vv65
Joined: 01 Mar 2015
Last visit: 10 Nov 2025
Posts: 534
Own Kudos:
395
 [1]
Given Kudos: 774
Location: India
GMAT 1: 740 Q47 V44
GMAT 1: 740 Q47 V44
Posts: 534
Kudos: 395
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
My answer is E (4)

If the wall were not there, the shadow of the 6 foot pillar would be 12 foot long
Because the shadow of the 1 foot pillar is 2 foot

The wall is 4 feet away from the pillar

By using the laws of similar triangles, we can see that x is 4
Attachments

20201217_231418.jpg
20201217_231418.jpg [ 1.88 MiB | Viewed 2896 times ]

User avatar
bumpbot
User avatar
Non-Human User
Joined: 09 Sep 2013
Last visit: 04 Jan 2021
Posts: 38,588
Own Kudos:
Posts: 38,588
Kudos: 1,079
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
Moderators:
Math Expert
105355 posts
Tuck School Moderator
805 posts