Question 251586
Smith engineering is in the process of reviewing the salaris of their surveyors. During this review the company foud that and experience surveyor can survey a roadbed in 3 hours. An apprentice surveyor needs 7 hours to survey the same stretch of road. 
If the two worked together find how long it takes them to complete the job.
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Experience surveyor rate : 1/3 job/hr
Apprentice rate: 1/7 job/hr
Together rate: 1/x job/hr
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Equation:
rate + rate + together rate:
1/3 + 1/7 = 1/x
7x + 3x = 21
10x = 21
x = 2.1 hours (time it will take if they work together)
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Cheers,
Stan H.