GMAT Changed on April 16th - Read about the latest changes here

 It is currently 21 May 2018, 13:48

### 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 June
Open Detailed Calendar

### Show Tags

26 Jul 2014, 10:36
4
KUDOS
8
This post was
BOOKMARKED
00:00

Difficulty:

15% (low)

Question Stats:

78% (00:58) correct 22% (00:34) wrong based on 281 sessions

### HideShow timer Statistics

A store sells erasers for 0.23$per piece and pencil for 0.11$ per piece. How many eraser and pencils did Jessica buy?

(1) She bough 5 erasers
(2) She spent total of 1.70$_________________ Like my post Send me a Kudos It is a Good manner. My Debrief: http://gmatclub.com/forum/how-to-score-750-and-750-i-moved-from-710-to-189016.html Math Expert Joined: 02 Sep 2009 Posts: 45222 Re: A store sells erasers for 0.23$ per piece and pencil for 0.1 [#permalink]

### Show Tags

26 Jul 2014, 10:47
A store sells erasers for 0.23$per piece and pencil for 0.11$ per piece. How many eraser and pencils did Jessica buy?

(1) She bough 5 erasers. Clearly insufficient.

(2) She spent total of 1.70$--> $$0.23e+0.11p=1.70$$ --> $$23e+11p=170$$ --> by trial and error we can find that the only non-negative integer solution for this equation is e=5 and p=5. Sufficient. Answer: B. _________________ Math Expert Joined: 02 Sep 2009 Posts: 45222 Re: A store sells erasers for 0.23$ per piece and pencil for 0.1 [#permalink]

### Show Tags

26 Jul 2014, 10:47
Bunuel wrote:
A store sells erasers for 0.23$per piece and pencil for 0.11$ per piece. How many eraser and pencils did Jessica buy?

(1) She bough 5 erasers. Clearly insufficient.

(2) She spent total of 1.70$--> $$0.23e+0.11p=1.70$$ --> $$23e+11p=170$$ --> by trial and error we can find that the only non-negative integer solution for this equation is e=5 and p=5. Sufficient. Answer: B. Similar questions to practice: eunice-sold-several-cakes-if-each-cake-sold-for-either-109602.html martha-bought-several-pencils-if-each-pencil-was-either-a-100204.html a-rental-car-agency-purchases-fleet-vehicles-in-two-sizes-a-105682.html joe-bought-only-twenty-cent-stamps-and-thirty-cent-stamps-106212.html a-certain-fruit-stand-sold-apples-for-0-70-each-and-bananas-101966.html joanna-bought-only-0-15-stamps-and-0-29-stamps-how-many-101743.html Hope it helps. _________________ Intern Joined: 17 Jan 2018 Posts: 38 Re: A store sells erasers for 0.23$ per piece and pencil for 0.1 [#permalink]

### Show Tags

21 Mar 2018, 23:11
Trial and error is too long and is not exhaustive enough.

There is a simpler solution.

Now, we know that 23x + 11y = 170

The units digit of 23 and 11 should add up to a 0.

So taking the units digit only ->

23x --> 3, 6, 9, 2, 5, 8, 1, 4, 7, 0
11y --> 1, 2, 3, 4, 5, 6, 7, 8, 9, 0

There are a lot of combinations, but trying the easiest first helps ->
(0,0)
23*10 + 11*10 = 340 !! (Voila) This is exactly double of what we need. Halve it.

So, x and y are 5 each.

(Cross checking with Option 1, we see that x is 5 is given, so we can be sure that this is the only answer)

Takes 45 seconds.

But, to be doubly sure, take some other combination in random, Say, (6, 4)

23*2 + 11*4 = 46 + 44 = 90 (Too low)

A bit higher is (5,5), almost confirmed. Have a leap of faith and mark B.

Bunuel wrote:
Bunuel wrote:
A store sells erasers for 0.23$per piece and pencil for 0.11$ per piece. How many eraser and pencils did Jessica buy?

(1) She bough 5 erasers. Clearly insufficient.

(2) She spent total of 1.70$--> $$0.23e+0.11p=1.70$$ --> $$23e+11p=170$$ --> by trial and error we can find that the only non-negative integer solution for this equation is e=5 and p=5. Sufficient. Answer: B. Similar questions to practice: http://gmatclub.com/forum/eunice-sold-s ... 09602.html http://gmatclub.com/forum/martha-bought ... 00204.html http://gmatclub.com/forum/a-rental-car- ... 05682.html http://gmatclub.com/forum/joe-bought-on ... 06212.html http://gmatclub.com/forum/a-certain-fru ... 01966.html http://gmatclub.com/forum/joanna-bought ... 01743.html Hope it helps. Manager Joined: 21 Jan 2018 Posts: 54 Location: India GPA: 2.85 WE: Consulting (Consulting) A store sells erasers for 0.23$ per piece and pencil for 0.1 [#permalink]

### Show Tags

01 Apr 2018, 22:44
honchos wrote:
A store sells erasers for 0.23$per piece and pencil for 0.11$ per piece. How many eraser and pencils did Jessica buy?

(1) She bough 5 erasers
(2) She spent total of 1.70$Given : P(Eraser) = 0.23 , P(Pencil) = 0,11 To find No. of Erasers and No. of Pencils Statement 1 : No of erasers = 5 , nut we cannot get the No of pencils --> Insufficient Statement 2 : 1.70 = 0.23*E + 0.11*P , we don't know values of E and P --> Sufficient Plus , E and P > 0 E = 5 P = 5 Option B _________________ Regards , Dhruv _________________ Kudos will encourage many others, like me. Please Give +1 Kudos if you liked the post!! Thanks A store sells erasers for 0.23$ per piece and pencil for 0.1   [#permalink] 01 Apr 2018, 22:44
Display posts from previous: Sort by