SOLUTION: Smith engineering is in the process of reviewing the salaries of their surveyors. During the review, the company found that an experienced surveyor can survey a roadbed in 6 hours

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Question 779089: Smith engineering is in the process of reviewing the salaries of their surveyors. During the review, the company found that an experienced surveyor can survey a roadbed in 6 hours. An apprentice surveyor needs 8 hours. If the two work together, find how long it takes them to complete the job.
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
experienced surveyor's rate:
( 1 roadbed surveyed ) / ( 6 hrs )
---------------------------
apprentice surveyor's rate:
( 1 roadbed surveyed ) / ( 8 hrs )
---------------------------
Let +t+ = their time in hrs to survey
the roadbed working together
Add the rates to get their rate working together
+1%2F6+%2B+1%2F8+=+1%2Ft+
Multiply both sides by +24t+
+4t+%2B+3t+=+24+
+7t+=+24+
+t+=+3.429+
+.429%2A60+=+26+
It takes them 3 hrs and 26 min
check:
+1%2F6+%2B+1%2F8+=+1%2F3.429+
+.1667+%2B+.125+=+.2916+
+.2917+=+.2916+
close enough