Bulbul was paid for the pens?

This topic has expert replies
User avatar
GMAT Instructor
Posts: 3650
Joined: Wed Jan 21, 2009 4:27 am
Location: India
Thanked: 267 times
Followed by:80 members
GMAT Score:760

Bulbul was paid for the pens?

by sanju09 » Fri Jan 01, 2010 2:42 am
Bulbul bought 5 pens, 7 pencils and 4 erasers. Baiju bought 6 pens, 8 erasers and 14 pencils for an amount which was half more than what Bulbul had paid. What percent of the total amount paid by Bulbul was paid for the pens?

(A) 37.5
(B) 43
(C) 50
(D) 62.5
(E) Data Insufficient
The mind is everything. What you think you become. -Lord Buddha



Sanjeev K Saxena
Quantitative Instructor
The Princeton Review - Manya Abroad
Lucknow-226001

www.manyagroup.com
Source: — Problem Solving |

GMAT Instructor
Posts: 1302
Joined: Mon Oct 19, 2009 2:13 pm
Location: Toronto
Thanked: 539 times
Followed by:164 members
GMAT Score:800

by Testluv » Fri Jan 01, 2010 3:49 am
sanju09 wrote:Bulbul bought 5 pens, 7 pencils and 4 erasers. Baiju bought 6 pens, 8 erasers and 14 pencils for an amount which was half more than what Bulbul had paid. What percent of the total amount paid by Bulbul was paid for the pens?

(A) 37.5
(B) 43
(C) 50
(D) 62.5
(E) Data Insufficient
Baiju has bought exactly twice the number of pencils and erasers that Bulbul has bought. Let the amount spent on pencils and erasers by Bulbul be x. Then, the amount spent by Baiju on pencils and erasers is 2x. Let the total amount that Bulbul paid be z. Then, the total amount that Baiju paid is 1.5z. Let price spent for each pen be y.

Then:

Bulbul: 5y + x = z

Baiju: 6y + 2x = 1.5z

and we need to solve for the fraction 5y/z (the fraction of total amount paid by Bulbul that was spent on pens). We can double Bulbul's equation, and then subtract Baiju's equation from that:

10y + 2x = 2z
6y + 2x = 1.5z
_____________

4y = z/2

y/z = 1/8; therefore, 5y/z = 5/8 or 62.5 percent.

Choose D.
Kaplan Teacher in Toronto

Junior | Next Rank: 30 Posts
Posts: 14
Joined: Sun Aug 23, 2009 8:09 am
Thanked: 1 times

by Resurgent » Fri Jan 01, 2010 7:49 am
Testluv wrote:Baiju has bought exactly twice the number of pencils and erasers that Bulbul has bought. Let the amount spent on pencils and erasers by Bulbul be x. Then, the amount spent by Baiju on pencils and erasers is 2x. Let the total amount that Bulbul paid be z. Then, the total amount that Baiju paid is 1.5z. Let price spent for each pen be y.

Then:

Bulbul: 5y + x = z

Baiju: 6y + 2x = 1.5z

and we need to solve for the fraction 5y/z (the fraction of total amount paid by Bulbul that was spent on pens). We can double Bulbul's equation, and then subtract Baiju's equation from that:

10y + 2x = 2z
6y + 2x = 1.5z
_____________

4y = z/2

y/z = 1/8; therefore, 5y/z = 5/8 or 62.5 percent.

Choose D.
Haha...that was a lateral thinking solution. Good one.

GMAT Instructor
Posts: 1302
Joined: Mon Oct 19, 2009 2:13 pm
Location: Toronto
Thanked: 539 times
Followed by:164 members
GMAT Score:800

by Testluv » Fri Jan 01, 2010 12:33 pm
Haha...that was a lateral thinking solution. Good one.
Thanks. I don't know where sanju gets them, but these are pretty fun questions.
Kaplan Teacher in Toronto

Master | Next Rank: 500 Posts
Posts: 392
Joined: Thu Jan 15, 2009 12:52 pm
Location: New Jersey
Thanked: 76 times

by truplayer256 » Fri Jan 01, 2010 2:16 pm
I think he makes these up on his own but here's how I did the problem.

PS= The price of each pen.

PE=The price of each pencil.

E=The price of each eraser.

5PS+7PE+4E=p

6PS+14PE+8E=3p/2

Notice that 14PE+8E=2(7PE+4E)

7PE+4E=p-5PS

6PS+2(p-5PS)=3p/2

-4PS=-p/2

p=8PS

5PS/8PS=5/8=0.625

GMAT Instructor
Posts: 1302
Joined: Mon Oct 19, 2009 2:13 pm
Location: Toronto
Thanked: 539 times
Followed by:164 members
GMAT Score:800

by Testluv » Fri Jan 01, 2010 2:24 pm
I think he makes these up on his own but here's how I did the problem.
I think you're right!
Kaplan Teacher in Toronto