It is currently 23 Jan 2018, 12:08

### 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

# A certain purse contains 30 coins, Each coin is either a nickel or

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
TAGS:

### Hide Tags

Intern
Joined: 05 Sep 2013
Posts: 9
Location: Georgia
A certain purse contains 30 coins, Each coin is either a nickel or [#permalink]

### Show Tags

17 Nov 2014, 03:24
1
KUDOS
1
This post was
BOOKMARKED
00:00

Difficulty:

35% (medium)

Question Stats:

74% (01:25) correct 26% (01:43) wrong based on 57 sessions

A certain purse contains 30 coins, Each coin is either a nickel or a quarter. If the total value of all coins in the purse is 4.70$, how many nickels does the purse contain? A. 12 B. 14 C. 16 D. 20 E. 22 [Reveal] Spoiler: OA Last edited by Bunuel on 17 Nov 2014, 10:37, edited 1 time in total. Edited the question. Manager Joined: 21 Jul 2014 Posts: 127 Re: A certain purse contains 30 coins, Each coin is either a nickel or [#permalink] ### Show Tags 17 Nov 2014, 07:23 1 This post received KUDOS NATABERI wrote: A certain purse contains 30 coins, Each coin is either a nickel or a quarter. If the total value of all coins in the purse is 4.70$, how many nickels does the purse contain?

To frame this as an equation:

n = number of nickels
q = number of quarters

1) $$.25q + .05n = 4.7$$
2) $$q + n = 30$$

So now you just need to solve for n.

$$q + n = 30$$
$$q = 30 - n$$

$$.25q + .05n = 4.7$$
$$.25(30-n) + .05n = 4.7$$
$$7.5 - .25n + .05n = 4.7$$
$$7.5 - .2n = 4.7$$
$$7.5 = 4.7 + .2n$$
$$7.5 - 4.7 = .2n$$
$$2.8 = .2n$$
$$2.8/.2 = n$$
$$14 = n$$

There are 14 nickels in the purse.
Manager
Joined: 10 Sep 2014
Posts: 98
Re: A certain purse contains 30 coins, Each coin is either a nickel or [#permalink]

### Show Tags

17 Nov 2014, 08:57
1
KUDOS
I picked a starting point and then kept ballparking until i hit the right answer

$4.70 - 6 quarters =$3.20. this would be 6 quarters and 64 nickels, WAY more than 30 so we need a lot more quarters

$4.70 - 16 quarters =$0.70 this would be 16 quarters and 14 nickels, 30 coins!

14 nickels!
SVP
Status: The Best Or Nothing
Joined: 27 Dec 2012
Posts: 1842
Location: India
Concentration: General Management, Technology
WE: Information Technology (Computer Software)
Re: A certain purse contains 30 coins, Each coin is either a nickel or [#permalink]

### Show Tags

20 Nov 2014, 22:57
Nickels ......................... Quarters ................ Total

0.05 ................................. 0.25 ................... 4.70 (Total Value)

x ................................... (30-x) ..................... 30 (Quantity)

Setting up the equation

0.05x + 0.25 (30-x) = 4.70

5x + 25(30-x) = 470

x + 5(30-x) = 94

x = 14

_________________

Kindly press "+1 Kudos" to appreciate

SVP
Joined: 11 Sep 2015
Posts: 2001
Re: A certain purse contains 30 coins, Each coin is either a nickel or [#permalink]

### Show Tags

15 Dec 2017, 15:30
Expert's post
Top Contributor
NATABERI wrote:
A certain purse contains 30 coins, Each coin is either a nickel or a quarter. If the total value of all coins in the purse is 4.70$, how many nickels does the purse contain? A. 12 B. 14 C. 16 D. 20 E. 22 ASIDE: Each nickel is worth 5 cents ($0.05) and each quarter is worth 25 cents ($0.25) Let n = the number of nickels in the purse This means (30-n) = the number of quarters in the purse (since there is a total of 30 COINS) Since each nickel is worth 5 cents, we know that n nickels is worth 5n CENTS Likewise, since each quarter is worth 25 cents, we know that (30-n) quarters is worth 25(30-n) CENTS The total value of all coins in the purse is$ 4.70
We can also say that the TOTAL value is 470 CENTS
So, we can write: (value of all nickels) + (value of all quarters) = 470 CENTS
Or: 5n + 25(30-n) = 470
Expand: 5n + 750 - 25n = 470
Simplify: -20n + 750 = 470
Subtract 750 from both sides: -20n = -280
Solve: n = 14

Cheers,
Brent
_________________

Brent Hanneson – Founder of gmatprepnow.com

Intern
Joined: 08 Dec 2017
Posts: 16
Re: A certain purse contains 30 coins, Each coin is either a nickel or [#permalink]

### Show Tags

15 Dec 2017, 18:22
The average value of a coin is 4.70/30 =.157
So about 16 cents. That is 11 cents more than a nickel and 9 cents less than a quarter. If there were an equal numbers of quarters and nickels the average would come out to 15 cents a coin. There there are slightly more quarters than nickels. 14 is the only viable answer.

Posted from my mobile device
Re: A certain purse contains 30 coins, Each coin is either a nickel or   [#permalink] 15 Dec 2017, 18:22
Display posts from previous: Sort by

# A certain purse contains 30 coins, Each coin is either a nickel or

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics

 Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.