Last Updated on May 11, 2023
GMAT OFFICIAL GUIDE DS
Solution:
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 the plumber charged for the two jobs.
Statement One Alone:
The plumber charged $92 for one of the two jobs.
We see that the job for which 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 for which 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, with a cost of $92. The two jobs will cost a total of $138 + $92 = $230. Statement two is sufficient to answer the question.
Answer: B
