GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 22 Feb 2019, 16:51

### 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

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

## Events & Promotions

###### Events & Promotions in February
PrevNext
SuMoTuWeThFrSa
272829303112
3456789
10111213141516
17181920212223
242526272812
Open Detailed Calendar
• ### Free GMAT RC Webinar

February 23, 2019

February 23, 2019

07:00 AM PST

09:00 AM PST

Learn reading strategies that can help even non-voracious reader to master GMAT RC. Saturday, February 23rd at 7 AM PT
• ### FREE Quant Workshop by e-GMAT!

February 24, 2019

February 24, 2019

07:00 AM PST

09:00 AM PST

Get personalized insights on how to achieve your Target Quant Score.

# What is the length of the line AD? (1) AC = 10, BD=15 (2) AB/BC=BC/CD

Author Message
TAGS:

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 53066
What is the length of the line AD? (1) AC = 10, BD=15 (2) AB/BC=BC/CD  [#permalink]

### Show Tags

16 Oct 2018, 23:38
00:00

Difficulty:

45% (medium)

Question Stats:

61% (01:37) correct 39% (01:46) wrong based on 54 sessions

### HideShow timer Statistics

What is the length of the line AD?

(1) AC = 10, BD = 15

(2) AB/BC = BC/CD

Attachment:

2018-10-17_1136.png [ 2.1 KiB | Viewed 387 times ]

_________________
Director
Joined: 18 Jul 2018
Posts: 679
Location: India
Concentration: Finance, Marketing
WE: Engineering (Energy and Utilities)
Re: What is the length of the line AD? (1) AC = 10, BD=15 (2) AB/BC=BC/CD  [#permalink]

### Show Tags

17 Oct 2018, 18:16
From statement 1:

AC = AB+BC = 10
BD = BC+CD = 15

AD = AB+BC+CD. Since BC is unknown. We cant determine the length of AD.
Insufficient.

From statement 2:

$$\frac{AB}{BC}$$ = $$\frac{BC}{CD}$$ Cross multiplying gives $$BC^2$$ = AB*CD.
Clearly Insufficient.

Combining both From 1:
AB = 10-BC
CD = 15-BC
From 2 $$BC^2$$ = AB*CD = (10-BC)(15-BC)
Solving gives BC as 6.

Sufficient.

C is the aswer.
_________________

Press +1 Kudo If my post helps!

Re: What is the length of the line AD? (1) AC = 10, BD=15 (2) AB/BC=BC/CD   [#permalink] 17 Oct 2018, 18:16
Display posts from previous: Sort by