Answer:
T = 3.5 hours
Step-by-step explanation:
this is a rate problem.
an experienced surveyor takes 7 hours to survey a roadbed
an apprentice surveyor takes 9 hours to survey a roadbed
the rate of the experienced surveyor =[tex]\frac{1}{7}[/tex]
the rate of the apprentice surveyor = [tex]\frac{1}{9}[/tex]
if the two work together , [tex]\frac{1}{T} =\frac{1}{7} +\frac{1}{9}[/tex]
T = [tex]\frac{56}{16}[/tex]
T = 3.5 hours
