If a phone call costs a cents for the first minute and a/3 cents : GMAT Problem Solving (PS)
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 22 Jan 2017, 01:08

### 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

# If a phone call costs a cents for the first minute and a/3 cents

Author Message
TAGS:

### Hide Tags

Moderator
Joined: 01 Sep 2010
Posts: 3091
Followers: 785

Kudos [?]: 6538 [1] , given: 1012

If a phone call costs a cents for the first minute and a/3 cents [#permalink]

### Show Tags

05 Oct 2012, 15:56
1
KUDOS
5
This post was
BOOKMARKED
00:00

Difficulty:

15% (low)

Question Stats:

82% (02:29) correct 18% (01:36) wrong based on 137 sessions

### HideShow timer Statistics

If a phone call costs a cents for the first minute and a/3 cents for each additional half-minute, how much a b minute phone call cost, in cents ?

A. $$\frac{(2a+2ab)}{27}$$

B. $$\frac{(a+2ab)}{3}$$

C. $$\frac{(a+ab)}{300}$$

D. $$\frac{(a+ab)}{3}$$

E. $$\frac{ab}{3}$$
[Reveal] Spoiler: OA

_________________
Intern
Joined: 28 Aug 2012
Posts: 46
Location: Austria
GMAT 1: 770 Q51 V42
Followers: 3

Kudos [?]: 43 [1] , given: 3

Re: If a phone call costs a cents for the first minute and a/3 cents [#permalink]

### Show Tags

05 Oct 2012, 21:19
1
KUDOS
First, let's set up an equation:

No matter how long the phone call is, we always have to pay a cents for the first minute. Every minute beyond the first minute costs 2a/3 cents.

Cost of phone call = a + (b-1) * 2a/3

Now we have to simplify this equation.

3a/3 + (b-1) * 2a/3
(3a + (b-1) * 2a) / 3
(3a + 2ab - 2a) / 3
(a + 2ab) / 3
Senior Manager
Joined: 13 Aug 2012
Posts: 464
Concentration: Marketing, Finance
GMAT 1: Q V0
GPA: 3.23
Followers: 25

Kudos [?]: 433 [1] , given: 11

Re: If a phone call costs a cents for the first minute and a/3 cents [#permalink]

### Show Tags

10 Dec 2012, 03:59
1
KUDOS
Cost = (1)(a) + ((b-1)/(1/2))(a/3)
Cost = a + (2b - 2)(a/3)
Cost = a + (2ab -2a)/3
Cost = (3a - 2a + 2ab) / 3
Cost = (a + 2ab)/3

_________________

Impossible is nothing to God.

GMAT Club Legend
Joined: 09 Sep 2013
Posts: 13494
Followers: 576

Kudos [?]: 163 [0], given: 0

Re: If a phone call costs a cents for the first minute and a/3 cents [#permalink]

### Show Tags

14 Nov 2014, 23:04
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
Manager
Joined: 30 May 2012
Posts: 99
Location: United States (TX)
Concentration: Finance, Marketing
GPA: 3.3
WE: Information Technology (Consulting)
Followers: 0

Kudos [?]: 53 [0], given: 82

Re: If a phone call costs a cents for the first minute and a/3 cents [#permalink]

### Show Tags

17 Dec 2014, 05:42
Could someone please help with this question? I thought "a b-minute" could also be half-a-minute in which case it costs a/2 cents. IOW, the cost of "b" minutes is ab, no?
Math Expert
Joined: 02 Sep 2009
Posts: 36590
Followers: 7092

Kudos [?]: 93390 [1] , given: 10557

If a phone call costs a cents for the first minute and a/3 cents [#permalink]

### Show Tags

17 Dec 2014, 05:55
1
KUDOS
Expert's post
Blackbox wrote:
If a phone call costs a cents for the first minute and a/3 cents for each additional half-minute, how much a b minute phone call cost, in cents ?

Could someone please help with this question? I thought "a b-minute" could also be half-a-minute in which case it costs a/2 cents. IOW, the cost of "b" minutes is ab, no?

A call less than or equal to 1 minute costs a cents. So, if b = 1/2 minutes the cost would still be a cents.

Easy way would be to just plug numbers, say a = 1 cent and b = 1 minute what would be the cost of a call then? It would cost 1 cent. Plug a = b = 1 and check for an option which would give 1. Only B fits.
_________________
Manager
Joined: 30 May 2012
Posts: 99
Location: United States (TX)
Concentration: Finance, Marketing
GPA: 3.3
WE: Information Technology (Consulting)
Followers: 0

Kudos [?]: 53 [0], given: 82

Re: If a phone call costs a cents for the first minute and a/3 cents [#permalink]

### Show Tags

17 Dec 2014, 06:06
Nice! It is much easier to sub-in values and understand. Thanks
Senior Manager
Status: Math is psycho-logical
Joined: 07 Apr 2014
Posts: 443
Location: Netherlands
GMAT Date: 02-11-2015
WE: Psychology and Counseling (Other)
Followers: 2

Kudos [?]: 109 [0], given: 169

Re: If a phone call costs a cents for the first minute and a/3 cents [#permalink]

### Show Tags

05 Jan 2015, 07:19
This is what I though after reading this:

First minute: a --> this actually means "a" times the number of minutes; in this case a*1.
Extra minutes: (2a)/3 --> a/3 for half a minute, so double this for a whole minute.
Based on the logic we used above to calculate the first minute, which is "a", the following minutes will be (2a)/3 times "b", because "b" is the number of minutes the person spoke.

Adding these: a + (2a)/3 times b, so a + (2ab)/3 --> ***if you write down the fractions horizontally it makes much more sense, because you don't use the parenthesis.
GMAT Club Legend
Joined: 09 Sep 2013
Posts: 13494
Followers: 576

Kudos [?]: 163 [0], given: 0

Re: If a phone call costs a cents for the first minute and a/3 cents [#permalink]

### Show Tags

16 Oct 2016, 20:39
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
Re: If a phone call costs a cents for the first minute and a/3 cents   [#permalink] 16 Oct 2016, 20:39
Similar topics Replies Last post
Similar
Topics:
2 A taxi company costs \$2.75 for the first quarter-mile and 12.5 cents 2 28 Jun 2016, 06:05
1 If electricity costs x cents per kilowatt-hour for the first 30 kilowa 4 29 Dec 2014, 07:22
17 To mail a package, the rate is x cents for the first pound 10 17 Dec 2012, 05:37
10 To mail a package, the rate is x cents for the first pound 11 25 Aug 2011, 08:02
8 To mail a package, the rate is x cents for the first pound and y cents 7 20 Jan 2008, 09:31
Display posts from previous: Sort by