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100 points for $49 worth of Veritas practice GMATs FREE VERITAS PRACTICE GMAT EXAMS Earn 10 Points Per Post Earn 10 Points Per Thanks Earn 10 Points Per Upvote The price of a phone call consists of a standard connection tagged by: swerve This topic has 3 expert replies and 0 member replies Top Member The price of a phone call consists of a standard connection Timer 00:00 Your Answer A B C D E Global Stats Difficult The price of a phone call consists of a standard connection fee, which is constant, plus a per minute charge. A 10-minute call costs$2.90 and a 16-minute call costs $4.40. How much does a 13-minute call cost? A.$3.55
B. $3.57 C.$3.58
D. $3.65 E.$3.77

The OA is D

Source: Manhattan Prep

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swerve wrote:
The price of a phone call consists of a standard connection fee, which is constant, plus a per minute charge. A 10-minute call costs $2.90 and a 16-minute call costs$4.40. How much does a 13-minute call cost?

A. $3.55 B.$3.57
C. $3.58 D.$3.65
E. $3.77 Let C = price of connection fee Let M = the price PER MINUTE A 10-minute call costs$2.90
We can write: C + 10M = 2.90

A 16-minute call costs $4.40. We can write: C + 16M = 4.40 How much does a 13-minute call cost? So far, we have: C + 10M = 2.90 C + 16M = 4.40 ONE (slower) approach would be to solve the system for C and M, and then calculate the cost of a 13-minute call. The FASTER approach is to recognize that something great happens when we ADD the two equations We get: 2C + 26M = 7.30 Now divide both sides by 2 to get: C + 13M = 3.65 Since C + 13M represents the TOTAL cost of a 13-minute call, we can conclude that a 13-minute call costs$3.65

Cheers,
Brent

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swerve wrote:
The price of a phone call consists of a standard connection fee, which is constant, plus a per minute charge. A 10-minute call costs $2.90 and a 16-minute call costs$4.40. How much does a 13-minute call cost?

A. $3.55 B.$3.57
C. $3.58 D.$3.65
E. $3.77 Source: Manhattan Prep $$? = f + 13c\,\,\,\,\left[ \ \right]$$ The constant fee (f) and the minute-charge (c) will be considered in CENTS. (Amounts in cents are always integers!) $$\left\{ \matrix{ \,f + 10c = 290 \hfill \cr \,f + 16c = 440 \hfill \cr} \right.\,\,\,\,\,\,\,\,\mathop \Rightarrow \limits^{\left( + \right)} \,\,\,\,\,\,2f + 26c = 290 + 440\,\,\,\,\,\,\mathop \Rightarrow \limits^{{\rm{focus}}\,!} \,\,\,\,\,\,? = {{2f + 26c} \over 2} = 145 + 220 = 365\,\,\,\,\,\,\left[ {\,{\rm{cents}}\,} \right]$$ This solution follows the notations and rationale taught in the GMATH method. Regards, Fabio. _________________ Fabio Skilnik :: GMATH method creator ( Math for the GMAT) English-speakers :: https://www.gmath.net Portuguese-speakers :: https://www.gmath.com.br GMAT/MBA Expert Elite Legendary Member Joined 23 Jun 2013 Posted: 10018 messages Followed by: 494 members Upvotes: 2867 GMAT Score: 800 Hi All, We're told that the price of a phone call consists of a standard connection fee, which is constant, plus a per minute charge, a 10-minute call costs$2.90 and a 16-minute call costs $4.40. We're asked for the cost of a 13-minute call. This question can be solved in a couple of different ways - and there's a great 'rate shortcut' that you can use to avoid some of the extra math that comes with certain approaches. Since there's a standard connection fee, we know that the difference between the costs of two calls is solely due to the number of minutes in the call. With the given information (about a 10-minute call and a 16-minute call), the difference in price comes down to the 6 minute difference in the length of the calls. Thus, the extra 6 minutes cost an extra$4.40 - $2.90 =$1.50. We're asked for the cost of a 13-minute call - which is exactly 'halfway' between those two prices. Half of $1.50 is$0.75, so we can add that to the cost of a 10-minute call to find the cost of the 13-minute call. $2.90 +$0.75 = $3.65 Final Answer: D GMAT assassins aren't born, they're made, Rich _________________ Contact Rich at Rich.C@empowergmat.com • Magoosh Study with Magoosh GMAT prep Available with Beat the GMAT members only code • 5-Day Free Trial 5-day free, full-access trial TTP Quant Available with Beat the GMAT members only code • Free Veritas GMAT Class Experience Lesson 1 Live Free Available with Beat the GMAT members only code • 1 Hour Free BEAT THE GMAT EXCLUSIVE Available with Beat the GMAT members only code • Award-winning private GMAT tutoring Register now and save up to$200

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