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

 It is currently 21 Oct 2018, 02:07

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

Of the land owned by a farmer, 90 percent was cleared for planting. Of

Author Message
TAGS:

Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 50007
Of the land owned by a farmer, 90 percent was cleared for planting. Of  [#permalink]

Show Tags

15 Oct 2015, 22:04
2
15
00:00

Difficulty:

15% (low)

Question Stats:

83% (01:47) correct 17% (02:02) wrong based on 955 sessions

HideShow timer Statistics

Of the land owned by a farmer, 90 percent was cleared for planting. Of the cleared land, 40 percent was planted with soybeans and 50 percent of the cleared land was planted with wheat. If the remaining 720 acres of cleared land was planted with corn, how many acres did the farmer own?

(A) 5,832
(B) 6,480
(C) 7,200
(D) 8,000
(E) 8,889

Kudos for a correct solution.

_________________
Director
Joined: 10 Mar 2013
Posts: 518
Location: Germany
Concentration: Finance, Entrepreneurship
GMAT 1: 580 Q46 V24
GPA: 3.88
WE: Information Technology (Consulting)
Re: Of the land owned by a farmer, 90 percent was cleared for planting. Of  [#permalink]

Show Tags

15 Oct 2015, 23:14
3
1
Bunuel wrote:
Of the land owned by a farmer, 90 percent was cleared for planting. Of the cleared land, 40 percent was planted with soybeans and 50 percent of the cleared land was planted with wheat. If the remaining 720 acres of cleared land was planted with corn, how many acres did the farmer own?

(A) 5,832
(B) 6,480
(C) 7,200
(D) 8,000
(E) 8,889

Kudos for a correct solution.

40% od 90% = 36%, 50% 0f 90% = 45% so the remaining 90-45-36=9%=720 acres or 10% of 90%=9% --> 720/9*100=80o0 acres Answer (D)
_________________

When you’re up, your friends know who you are. When you’re down, you know who your friends are.

800Score ONLY QUANT CAT1 51, CAT2 50, CAT3 50
GMAT PREP 670
MGMAT CAT 630
KAPLAN CAT 660

Verbal Forum Moderator
Status: Greatness begins beyond your comfort zone
Joined: 08 Dec 2013
Posts: 2086
Location: India
Concentration: General Management, Strategy
Schools: Kelley '20, ISB '19
GPA: 3.2
WE: Information Technology (Consulting)
Re: Of the land owned by a farmer, 90 percent was cleared for planting. Of  [#permalink]

Show Tags

16 Oct 2015, 02:14
3
1
Percentage cleared for planting = 90
Soybean = 40% of 90 = 36 % of total
Wheat = 50 % of 90 =45 % of total
Corn = 10 % of 90 = 9 % of total

Since 9% of total = 720 acres
Therefore , total land = 720/9 * 100 = 8000 acres

_________________

When everything seems to be going against you, remember that the airplane takes off against the wind, not with it. - Henry Ford
The Moment You Think About Giving Up, Think Of The Reason Why You Held On So Long
+1 Kudos if you find this post helpful

Manager
Joined: 02 Jul 2015
Posts: 106
Schools: ISB '18
GMAT 1: 680 Q49 V33
Re: Of the land owned by a farmer, 90 percent was cleared for planting. Of  [#permalink]

Show Tags

16 Oct 2015, 02:40
1
IMO 8000

9 out of 100 corresponds to 720 out of 8000.
Manager
Joined: 26 Dec 2012
Posts: 146
Location: United States
Concentration: Technology, Social Entrepreneurship
WE: Information Technology (Computer Software)
Re: Of the land owned by a farmer, 90 percent was cleared for planting. Of  [#permalink]

Show Tags

16 Oct 2015, 18:52
1
Let farmer has X land;
Cleaned =.9 x
out of .9 x 10% is 720 ; therefore .09x=720 => x=8000

Thanks
Manager
Joined: 13 Mar 2013
Posts: 166
Location: United States
GPA: 3.5
WE: Engineering (Telecommunications)
Re: Of the land owned by a farmer, 90 percent was cleared for planting. Of  [#permalink]

Show Tags

16 Oct 2015, 20:58
1
Of the land owned by a farmer, 90 percent was cleared for planting. Of the cleared land, 40 percent was planted with soybeans and 50 percent of the cleared land was planted with wheat. If the remaining 720 acres of cleared land was planted with corn, how many acres did the farmer own?

(A) 5,832
(B) 6,480
(C) 7,200
(D) 8,000
(E) 8,889

For this type of Question its always better to go by option and elimination plays a key role here .

As per the Q -- out of the total land -- 90% was cleared for planting .

now see the option --- only B,C, D will give you a integer value .When we do 90% of total Area.

hence A,E can be eliminated .

Option B -- 6480 * (90/100) = 5832
5832 * ( 40/100 ) = wont give us a integer value . Hence can be eliminated .

Option C and D left .
Now see option D is good number to start with because its value .( 8000)

When we apply 8000( 90/100) = 7200 (50/100) = 3600
7200(40/100)= 2880

Now sum them = 2880 + 3600 = 6480

If the remaining 720 acres of cleared land was planted with corn .

This remaining area comes from 7200 - 6480 = 720 .

Hence the condition got satisfied .

Ans is D .
_________________

Regards ,

Target Test Prep Representative
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 3896
Location: United States (CA)
Re: Of the land owned by a farmer, 90 percent was cleared for planting. Of  [#permalink]

Show Tags

02 May 2016, 08:55
3
1
Bunuel wrote:
Of the land owned by a farmer, 90 percent was cleared for planting. Of the cleared land, 40 percent was planted with soybeans and 50 percent of the cleared land was planted with wheat. If the remaining 720 acres of cleared land was planted with corn, how many acres did the farmer own?

(A) 5,832
(B) 6,480
(C) 7,200
(D) 8,000
(E) 8,889

Kudos for a correct solution.

Solution:

We can start by letting T = the total land owned by the farmer. Since 90% was cleared for farming we can say:

0.9T = cleared for farming

We are next given that of the cleared land, 40 percent was planted with soybeans. This can be represented as:

0.4(0.9T) = planted with soybeans

0.36T = planted with soybeans

Next we are given that 50 percent of the cleared land was planted with wheat. This can be represented as:

0.5(0.9T) = 0.45T

Finally, we are given that the remaining 720 acres of cleared land was planted with corn. Thus, we can create the following equation:

0.36T + 0.45T + 720 = 0.9T

0.81T + 720 = 0.9T

720 = 0.09T

72,000 = 9T

T = 8,000

_________________

Scott Woodbury-Stewart
Founder and CEO

GMAT Quant Self-Study Course
500+ lessons 3000+ practice problems 800+ HD solutions

Director
Status: Professional GMAT Tutor
Affiliations: AB, cum laude, Harvard University (Class of '02)
Joined: 10 Jul 2015
Posts: 671
Location: United States (CA)
Age: 38
GMAT 1: 770 Q47 V48
GMAT 2: 730 Q44 V47
GMAT 3: 750 Q50 V42
GRE 1: Q168 V169
WE: Education (Education)
Re: Of the land owned by a farmer, 90 percent was cleared for planting. Of  [#permalink]

Show Tags

10 May 2016, 17:55
3
Attached is a visual that should help.
Attachments

Screen Shot 2016-05-10 at 5.48.46 PM.png [ 67.68 KiB | Viewed 9812 times ]

_________________

Harvard grad and 99% GMAT scorer, offering expert, private GMAT tutoring and coaching, both in-person (San Diego, CA, USA) and online worldwide, since 2002.

One of the only known humans to have taken the GMAT 5 times and scored in the 700s every time (700, 710, 730, 750, 770), including verified section scores of Q50 / V47, as well as personal bests of 8/8 IR (2 times), 6/6 AWA (4 times), 50/51Q and 48/51V (1 question wrong).

You can download my official test-taker score report (all scores within the last 5 years) directly from the Pearson Vue website: https://tinyurl.com/y94hlarr Date of Birth: 09 December 1979.

GMAT Action Plan and Free E-Book - McElroy Tutoring

Contact: mcelroy@post.harvard.edu (I do not respond to PMs on GMAT Club.)

...or find me on Reddit: http://www.reddit.com/r/GMATpreparation

Manager
Status: One Last Shot !!!
Joined: 04 May 2014
Posts: 239
Location: India
Concentration: Marketing, Social Entrepreneurship
GMAT 1: 630 Q44 V32
GMAT 2: 680 Q47 V35
Re: Of the land owned by a farmer, 90 percent was cleared for planting. Of  [#permalink]

Show Tags

10 May 2016, 19:58
1
(10% of (90% of total land)) is 720

$$0.1 * 0.9 * X = 720$$

$$X = 8000$$

Option D
_________________

One Kudos for an everlasting piece of knowledge is not a bad deal at all...

------------------------------------------------------------------------------------------------------------------------
Twenty years from now you will be more disappointed by the things you didn't do than by the ones you did do. So throw off the bowlines. Sail away from the safe harbor. Catch the trade winds in your sails. Explore. Dream. Discover.
-Mark Twain

Intern
Joined: 01 Feb 2016
Posts: 4
Location: Honduras
Concentration: Operations, Economics
GPA: 3.3
WE: Supply Chain Management (Transportation)
Re: Of the land owned by a farmer, 90 percent was cleared for planting. Of  [#permalink]

Show Tags

21 Jun 2016, 11:12
1
I understand it the following way:
0.40(90)+0.50(90)+720=0.90x
2880+3600+720=0.90x
7200=0.90x
$$\frac{7200}{0.90}$$=x
8000=x
Manager
Joined: 20 Mar 2015
Posts: 60
Of the land owned by a farmer, 90 percent was cleared for planting. Of  [#permalink]

Show Tags

24 Jun 2016, 04:55
Bunuel wrote:
Of the land owned by a farmer, 90 percent was cleared for planting. Of the cleared land, 40 percent was planted with soybeans and 50 percent of the cleared land was planted with wheat. If the remaining 720 acres of cleared land was planted with corn, how many acres did the farmer own?

(A) 5,832
(B) 6,480
(C) 7,200
(D) 8,000
(E) 8,889

Kudos for a correct solution.

Suppose the total land was 100. Then, 90% of 100 = 90.

Of the 90, 40%(36) of land was used for soyabeans, 50%(45) was for wheat. Remaining land portion of 90 is 9.

According to question 9 equals 720.

By unitary method.
If;
9(land) = 720
then;
100(land) =x(what).

By cross multiplication.

x = $$720*100/9$$

= 8000.

D.
Intern
Joined: 08 Oct 2016
Posts: 1
Re: Of the land owned by a farmer, 90 percent was cleared for planting. Of  [#permalink]

Show Tags

13 Nov 2016, 23:23
Hi,

Is this a right approach [or an unnecessarily longer one?]

In the cleared land : 720 is 10%
Hence, 720*4 = 2880 is 40%
and, 720*5 = 3600 is 50%

Adding all these the 90% cleared land turns out to be 7200, the remaining has to be 800. Hence 7200+800 = 8000 -> Answer D.
Manager
Joined: 25 Mar 2013
Posts: 247
Location: United States
Concentration: Entrepreneurship, Marketing
GPA: 3.5
Re: Of the land owned by a farmer, 90 percent was cleared for planting. Of  [#permalink]

Show Tags

22 Dec 2016, 14:37
0.4 x 0.9X = 0.36X = Soybean
0.5 x 0.9X = 0.45X = Wheat
0.36x + 0.45x + 720 = 0.9x
0.81x + 720 = 0.9x
x = 8000
D
_________________

I welcome analysis on my posts and kudo +1 if helpful. It helps me to improve my craft.Thank you

EMPOWERgmat Instructor
Status: GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 12687
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Re: Of the land owned by a farmer, 90 percent was cleared for planting. Of  [#permalink]

Show Tags

03 Feb 2018, 16:36
Hi All,

This question can be solved by TESTing THE ANSWERS. From the prompt, we know that we're going to be doing a number of small calculations AND we're going to end with 720 acres remaining for corn. Since we're asked for the total number of acres, and the answers are all numbers, we just have to work until we find the one that matches what we've been told. In these situations, it's often best to start with Answer B or D. Between those 2 options, D looks 'nicer'/easier, so let's start there.

IF....there were 8000 total acres...

90% was cleared for planting = (.9)(8000) = 7200 acres for planting

Of that land,
40% was soybeans = (4.)(7200) = 2880 acres
50% was wheat = (.5)(7200) = 3600

2880 + 3600 = 6480

7200 - 6480 = 720 --> this is an exact match for what we were told, so this MUST be the answer.

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

760+: Learn What GMAT Assassins Do to Score at the Highest Levels
Contact Rich at: Rich.C@empowergmat.com

Rich Cohen

Co-Founder & GMAT Assassin

Special Offer: Save \$75 + GMAT Club Tests Free
Official GMAT Exam Packs + 70 Pt. Improvement Guarantee
www.empowergmat.com/

*****Select EMPOWERgmat Courses now include ALL 6 Official GMAC CATs!*****

Study Buddy Forum Moderator
Joined: 04 Sep 2016
Posts: 1210
Location: India
WE: Engineering (Other)
Re: Of the land owned by a farmer, 90 percent was cleared for planting. Of  [#permalink]

Show Tags

12 May 2018, 04:26
Bunuel niks18 gmatbusters chetan2u VeritasPrepKarishma

Quote:
Of the land owned by a farmer, 90 percent was cleared for planting. Of the cleared land, 40 percent was planted with soybeans and 50 percent of the cleared land was planted with wheat. If the remaining 720 acres of cleared land was planted with corn, how many acres did the farmer own?

Usually in percentage problems, do not we take final value as 100 and back solve?

Eg: Say total acres of farm owned = 100

Cleared for farming: 90 acres
Of cleared farm: 40% ie 36 acres planted with SB
Of cleared farm: 50% ie 45 acres planted with W
Total SB + W : 91 acres

Remaining 9 acres: planted with corn.

Now 9x= 720 or x = 60

Let us set up a proportion: SB : W: C = 36 : 45 : 9
or 4 :5 : 1 or 10 * x = 600

_________________

It's the journey that brings us happiness not the destination.

Senior DS Moderator
Joined: 27 Oct 2017
Posts: 912
Location: India
GPA: 3.64
WE: Business Development (Energy and Utilities)
Re: Of the land owned by a farmer, 90 percent was cleared for planting. Of  [#permalink]

Show Tags

12 May 2018, 04:50
1
36+45 =81x
now remaining cleared land = 90-81 = 9x
Now 9x = 720: x =80
So total land = 100x = 8000

Quote:
Of the land owned by a farmer, 90 percent was cleared for planting. Of the cleared land, 40 percent was planted with soybeans and 50 percent of the cleared land was planted with wheat. If the remaining 720 acres of cleared land was planted with corn, how many acres did the farmer own?

Usually in percentage problems, do not we take final value as 100 and back solve?

Eg: Say total acres of farm owned = 100x

Cleared for farming: 90x acres
Of cleared farm: 40% ie 36 x acres planted with SB
Of cleared farm: 50% ie 45 x acres planted with W
Total SB + W : 91 acres - CALCULATION ERROR

Remaining 9 acres: planted with corn.

Now 9x= 720 or x = 60 again CALCULATION ERROR

Let us set up a proportion: SB : W: C = 36 : 45 : 9
or 4 :5 : 1 or 10 * x = 600
- NOT required. see my approach in last steps

_________________
Re: Of the land owned by a farmer, 90 percent was cleared for planting. Of &nbs [#permalink] 12 May 2018, 04:50
Display posts from previous: Sort by