Batch of cookies

BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

This topic has expert replies

Post new topic Post Reply

Previous Topic Next Topic

jessicamuniz: Junior | Next Rank: 30 Posts; Posts: 26; Joined: Thu Jul 17, 2008 1:02 pm

Batch of cookies

by jessicamuniz » Mon Nov 03, 2008 2:11 pm

Hi everyone....
Here is Q.

A batch of cookies is distributed among three children. One child gets 1/6 of the cookies, another child gest 1/5 of the cookies, and the third child gets 1/3 of the cookies. If there are 18 cookies remaining, how many cookies were in the entire batch?
a. 48
b.54
c.60
d.72
e.108

it is easy but I would like to see different options.
Thanks

Quote

Source: Beat The GMAT — Problem Solving | Mon Nov 03, 2008 2:11 pm

cramya: Legendary Member; Posts: 2467; Joined: Thu Aug 28, 2008 6:14 pm; Thanked: 331 times; Followed by:11 members

by cramya » Mon Nov 03, 2008 2:34 pm

Is the OA 60?

If its right I will post the soln.

Please post the OA's using spoiler function if possible

Eg: [spoiler]OA: whatever the oa is[/spoiler]

Quote

earth@work: Master | Next Rank: 500 Posts; Posts: 248; Joined: Mon Aug 11, 2008 9:51 am; Thanked: 13 times

by earth@work » Mon Nov 03, 2008 2:45 pm

even i get 60

Quote

jessicamuniz: Junior | Next Rank: 30 Posts; Posts: 26; Joined: Thu Jul 17, 2008 1:02 pm

Re. batch cookies

by jessicamuniz » Mon Nov 03, 2008 2:46 pm

Hi Cramya:
The thing is that I do not have the answer and I got the same answer as you by picking numbers.
I am looking for an answer that actually gives me an idea of how to solve it.
I got:
1/6x+1/5x+1/3x + 18.....but in this case I get a wrong answer, that is why I picked numbers....Why don't you post how did you solve it.
Thanks a lot.

Quote

jaybrium: Senior | Next Rank: 100 Posts; Posts: 37; Joined: Wed Sep 10, 2008 12:16 pm; Location: Glendale, AZ; Thanked: 3 times; Followed by:1 members

by jaybrium » Mon Nov 03, 2008 3:03 pm

I got 60:

X= total amount of cookies
x/6 went to the first child
x/5 went to the second child
x/3 went to the third child
18 cookies remain

therefore

X - (X/6) - (X/5) - (X/3) = 18

X - (5X/30) - (6X/30) - (10X/30) = 18

X - (21X/30) = 18

X(1-[21/30]) = 18

X(9/30) = 18

X = 18 / (9/30)

X = 60

- Jay

Quote

Hope700: Newbie | Next Rank: 10 Posts; Posts: 7; Joined: Tue Oct 28, 2008 2:58 pm; Thanked: 1 times

excelent explanation I agree with it

by Hope700 » Mon Nov 03, 2008 3:28 pm

60 is the answer

Quote

cramya: Legendary Member; Posts: 2467; Joined: Thu Aug 28, 2008 6:14 pm; Thanked: 331 times; Followed by:11 members

by cramya » Mon Nov 03, 2008 5:02 pm

I think Jay's solution work too

Let x be the total

(The way I did it was get 1/6,1/5,1/3 to a fraction with their LCM)

1/6x+1/5x+1/3x = 21x/30

The remaining part must be 9x/30

Given 9x/30=18
x=60

Hope thsi helps!

Quote

vishubn: Legendary Member; Posts: 574; Joined: Sun Jun 01, 2008 8:48 am; Location: Bangalore; Thanked: 28 times

by vishubn » Tue Nov 04, 2008 5:57 am

x/6+x/5+x/3+18=x

((15x+18x+30x)/90)+18=x
(63x/90)-x=18
x-(7x/10)=18
3x/10=18
3x=180
x=60 cookies

Vishu

Quote

logitech: Legendary Member; Posts: 2134; Joined: Mon Oct 20, 2008 11:26 pm; Thanked: 237 times; Followed by:25 members; GMAT Score:730