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Register now and save up to $200 Available with Beat the GMAT members only code • Free Practice Test & Review How would you score if you took the GMAT Available with Beat the GMAT members only code • 5 Day FREE Trial Study Smarter, Not Harder Available with Beat the GMAT members only code ## A certain plumber charges$92 for each job completed

tagged by: Brent@GMATPrepNow

This topic has 2 expert replies and 0 member replies
jjjinapinch Senior | Next Rank: 100 Posts
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(2) The plumber charged $138 for one of the two jobs. Official Guide question Answer: B Need free GMAT or MBA advice from an expert? Register for Beat The GMAT now and post your question in these forums! ### GMAT/MBA Expert Brent@GMATPrepNow GMAT Instructor Joined 08 Dec 2008 Posted: 10989 messages Followed by: 1217 members Thanked: 5251 times GMAT Score: 770 Tue Aug 01, 2017 10:21 am jjjinapinch wrote: A certain plumber charges$92 for each job completed in 4 hours or less and $23 per hour for each job completed in more than 4 hours. If it took the plumber a total of 7 hours to complete two separate jobs, what was the total amount charged by the plumber for the two jobs? (1) The plumber charged$92 for one of the two jobs.
(2) The plumber charged $138 for one of the two jobs. Official Guide question Answer: B Target question: What was the total amount charged by the plumber for the two jobs? Given:$92 for each job completed in 4 hours or less. $23 per hour for each job completed in more than 4 hours. Total work time was 7 hours Statement 1: The plumber charged$92 for one of the two jobs
This statement doesn't FEEL sufficient, so I'll TEST some values.
There are several scenarios that satisfy statement 1. Here are two:
Case a: the plumber spent 1 hour on one job (and received $92) and spent 6 hours on the other job (at$23/hours). In this case, the TOTAL amount charged = $92 + (6)($23) = $230 Case b: the plumber spent 2 hours on one job (and received$92) and spent 5 hours on the other job (at $23/hours). In this case, the TOTAL amount charged =$92 + (5)($23) =$207
Since we cannot answer the target question with certainty, statement 1 is NOT SUFFICIENT

Aside: For more on this idea of plugging in values when a statement doesn't feel sufficient, read my article: http://www.gmatprepnow.com/articles/data-sufficiency-when-plug-values

Statement 2: The plumber charged $138 for one of the two jobs. This means the plumber MUST have spent more than 4 hours on this job So, the rate charged is$23/hour
$138/23 = 6. So, the plumber spent 6 hours on this job (and received$138), which means he spent 1 hour on the other job (and received $92) So, the TOTAL amount charged =$138 + $92 =$230
Since we can answer the target question with certainty, statement 2 is SUFFICIENT

Cheers,
Brent

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Jeff@TargetTestPrep GMAT Instructor
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Wed Aug 09, 2017 11:12 am
jjjinapinch wrote:
A certain plumber charges $92 for each job completed in 4 hours or less and$23 per hour for each job completed in more than 4 hours. If it took the plumber a total of 7 hours to complete two separate jobs, what was the total amount charged by the plumber for the two jobs?

(1) The plumber charged $92 for one of the two jobs. (2) The plumber charged$138 for one of the two jobs.

Official Guide question
We are given that a certain plumber charges $92 for each job completed in 4 hours or less and$23 per hour for each job completed in more than 4 hours. We are also given that it took the plumber a total of 7 hours to complete two separate jobs, and we need to determine the total amount charged by the plumber for the two jobs.

Statement One Alone:

The plumber charged $92 for one of the two jobs. We see that the job he charged$92 could be 1, 2, 3, or even 4 hours long, which means the other job was 6, 5, 4, or 3 hours, respectively. Thus, we cannot determine the total amount charged for the two jobs. Statement one alone is not sufficient to answer the question.

Statement Two Alone:

The plumber charged $138 for one of the two jobs. We see that the job he charged$138 must be longer than 4 hours. Since he charges $23 per hour for a job that is longer than 4 hours, we have: 138 = 23(number of hours) 6 = number of hours Thus, the other job must have taken 1 hour and cost$92. The two jobs will cost a total of $138 +$92 = \$230. Statement two is sufficient to answer the question.

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