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

 It is currently 14 Dec 2019, 11:32

### 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

# In the figure, lines l and k are parallel. If a is an acute angle, the

Author Message
TAGS:

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 59725
In the figure, lines l and k are parallel. If a is an acute angle, the  [#permalink]

### Show Tags

Updated on: 22 Jul 2019, 05:46
00:00

Difficulty:

15% (low)

Question Stats:

91% (02:02) correct 9% (04:07) wrong based on 23 sessions

### HideShow timer Statistics

In the figure, lines $$l$$ and $$k$$ are parallel. If a is an acute angle, then which one of the following must be true?

(A) $$b > 10$$

(B) $$b > 15$$

(C) $$b < 20$$

(D) $$b < 30$$

(E) $$b > 45$$

Source: Nova GMAT
Difficulty Level: 550

Attachment:

#GREpracticequestion In the figure, lines l and k are parallel.jpg [ 18.37 KiB | Viewed 639 times ]

_________________

Originally posted by Bunuel on 18 Mar 2019, 00:03.
Last edited by SajjadAhmad on 22 Jul 2019, 05:46, edited 1 time in total.
GMAT Club Legend
Joined: 18 Aug 2017
Posts: 5483
Location: India
Concentration: Sustainability, Marketing
GPA: 4
WE: Marketing (Energy and Utilities)
Re: In the figure, lines l and k are parallel. If a is an acute angle, the  [#permalink]

### Show Tags

Updated on: 20 Mar 2019, 10:13
1
Bunuel wrote:

In the figure, lines $$l$$ and $$k$$ are parallel. If a is an acute angle, then which one of the following must be true?

(A) $$b > 10$$

(B) $$b > 15$$

(C) $$b < 20$$

(D) $$b < 30$$

(E) $$b > 45$$

Attachment:
The attachment #GREpracticequestion In the figure, lines l and k are parallel.jpg is no longer available

solution attached
AjjayKannan
anshkool4u
Attachments

File comment: Solution attached

IMG_20190320_224102905.jpg [ 3.52 MiB | Viewed 425 times ]

Originally posted by Archit3110 on 18 Mar 2019, 01:27.
Last edited by Archit3110 on 20 Mar 2019, 10:13, edited 2 times in total.
Intern
Joined: 26 Dec 2018
Posts: 21
Re: In the figure, lines l and k are parallel. If a is an acute angle, the  [#permalink]

### Show Tags

20 Mar 2019, 09:15
an explanation for the answer, please. Option E seems to be the right one
Manager
Joined: 18 Oct 2018
Posts: 90
Location: India
GMAT 1: 710 Q50 V36
GPA: 4
Re: In the figure, lines l and k are parallel. If a is an acute angle, the  [#permalink]

### Show Tags

Updated on: 20 Mar 2019, 09:33
Consider another line m parallel to line k and l,passing through angle b,dividing the angle into angle X and angle a-x.
Now,between angle m and l,angle b+30=angle X
Thus,b+30=X

Between angle k and m,angle b=angle a-x

Thus,angle a=X+a-x= b+30+b=2b+30

Given angle a is acute.
Thus,2b+30<90
b<30.
Hence b.

Press Kudos if u liked my solution

Posted from my mobile device

Originally posted by anshkool4u on 20 Mar 2019, 09:25.
Last edited by anshkool4u on 20 Mar 2019, 09:33, edited 1 time in total.
Intern
Joined: 26 Dec 2018
Posts: 21
Re: In the figure, lines l and k are parallel. If a is an acute angle, the  [#permalink]

### Show Tags

20 Mar 2019, 09:29
anshkool4u wrote:
Consider another line m parallel to line k and l,passing through angle b,dividing the angle into angle X and angle a-x.
Now,between angle m and l,angle b+30=angle X
Thus,b+30=X

Between angle k and m,angle b=angle a-x

Thus,angle a=X+a-x= b+30+b=2b+30

Given angle a is obtuse.
Thus,2b+30<90
b<30.
Hence b.

Press Kudos if u liked my solution

Posted from my mobile device

Angle a is acute not obtuse
Manager
Joined: 18 Oct 2018
Posts: 90
Location: India
GMAT 1: 710 Q50 V36
GPA: 4
Re: In the figure, lines l and k are parallel. If a is an acute angle, the  [#permalink]

### Show Tags

20 Mar 2019, 09:33
Sorry for the typing mistake.
But I hope,u must have got the clear intent from the solution

Posted from my mobile device
Intern
Joined: 26 Dec 2018
Posts: 21
Re: In the figure, lines l and k are parallel. If a is an acute angle, the  [#permalink]

### Show Tags

Updated on: 20 Mar 2019, 10:17
if b+30 is alternate angle and by sum of all angles in a triangle is 180 logic.

[m]B+30 + B + 180 - a = 180[/m]

which is [m]B = [fraction](a-30)/2[/fraction][/m]

When a is acute angle, B will always be equal and below 30 degrees.

Anything wrong in this?

Originally posted by AjjayKannan on 20 Mar 2019, 09:46.
Last edited by AjjayKannan on 20 Mar 2019, 10:17, edited 1 time in total.
Manager
Joined: 18 Oct 2018
Posts: 90
Location: India
GMAT 1: 710 Q50 V36
GPA: 4
Re: In the figure, lines l and k are parallel. If a is an acute angle, the  [#permalink]

### Show Tags

20 Mar 2019, 10:10
Nothing wrong in this solution.
The only mistake is in the last line,B=(a-30)/2.
For any value of a between 0-89,b will be less than 30 degree.

Ex. When a=89,b=29.5
When a=30,b=0

Posted from my mobile device
Re: In the figure, lines l and k are parallel. If a is an acute angle, the   [#permalink] 20 Mar 2019, 10:10
Display posts from previous: Sort by