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

 It is currently 16 Dec 2018, 13:10

### 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 December
PrevNext
SuMoTuWeThFrSa
2526272829301
2345678
9101112131415
16171819202122
23242526272829
303112345
Open Detailed Calendar
• ### Free GMAT Prep Hour

December 16, 2018

December 16, 2018

03:00 PM EST

04:00 PM EST

Strategies and techniques for approaching featured GMAT topics
• ### FREE Quant Workshop by e-GMAT!

December 16, 2018

December 16, 2018

07:00 AM PST

09:00 AM PST

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

# AB and CD are both diameters of a circle with centre O. So A, B, C, D

Author Message
TAGS:

### Hide Tags

DS Forum Moderator
Joined: 21 Aug 2013
Posts: 1412
Location: India
AB and CD are both diameters of a circle with centre O. So A, B, C, D  [#permalink]

### Show Tags

04 Jul 2018, 22:20
00:00

Difficulty:

25% (medium)

Question Stats:

82% (01:41) correct 18% (01:29) wrong based on 19 sessions

### HideShow timer Statistics

AB and CD are both diameters of a circle with centre O. So A, B, C, D all lie on the circumference of the circle. Sum of areas of sector AOC and sector BOD is what fraction of the total area of the circle?

(1) Angle AOD = 100 degrees.

(2) Angle AOC = 80 degrees.
examPAL Representative
Joined: 07 Dec 2017
Posts: 841
Re: AB and CD are both diameters of a circle with centre O. So A, B, C, D  [#permalink]

### Show Tags

04 Jul 2018, 22:53
amanvermagmat wrote:
AB and CD are both diameters of a circle with centre O. So A, B, C, D all lie on the circumference of the circle. Sum of areas of sector AOC and sector BOD is what fraction of the total area of the circle?

(1) Angle AOD = 100 degrees.

(2) Angle AOC = 80 degrees.

Questions like these, which talk about a figure without giving it, are much easier to answer if we draw them out first.
This is an Alternative approach.

(1) Drawing a circle with two diameters and writing in AOD = 100, we can fill the angle opposite to it to be 100. Since the 4 angles sum to 360, the remaining two sum to 360 - 200 = 160.
So sectors AOC and BOD are proportional to 160 degrees of the circle meaning they have 160/360 of the area.
Sufficient.

(2) repeating the same process as above gives us exactly the same values.
Sufficient.

_________________
Director
Status: Learning stage
Joined: 01 Oct 2017
Posts: 931
WE: Supply Chain Management (Energy and Utilities)
Re: AB and CD are both diameters of a circle with centre O. So A, B, C, D  [#permalink]

### Show Tags

05 Jul 2018, 00:04
Quote:
amanvermagmat wrote:
AB and CD are both diameters of a circle with centre O. So A, B, C, D all lie on the circumference of the circle. Sum of areas of sector AOC and sector BOD is what fraction of the total area of the circle?

(1) Angle AOD = 100 degrees.

(2) Angle AOC = 80 degrees.

Please refer the affixed diagram for the explanation.

Both statements are alone sufficient.

Ans. (D)
Attachments

Sector.JPG [ 34.55 KiB | Viewed 341 times ]

_________________

Regards,

PKN

Rise above the storm, you will find the sunshine

Re: AB and CD are both diameters of a circle with centre O. So A, B, C, D &nbs [#permalink] 05 Jul 2018, 00:04
Display posts from previous: Sort by