Answer: Contractor's crew can frame 54 houses in 18 weeks.
Explanation:-
Time taken to complete 3 houses=1 weeks
⇒Time taken to complete 1 house=\(\frac{1}{3}\) week
⇒Time taken to complete 54 houses =\(\frac{54}{3}\) weeks
=18 weeks
Therefore, contractor's crew can frame 54 houses in 18 weeks.