Answer:
Option (c) is correct.
Step-by-step explanation:
Lawrence can complete a task in three hours and will be paid:
= $20 × 3 hours
= $60
Three hours payment for Kelly:
= $90 × 3 hours
= $270
Kelly has more architectural jobs than she is able to handle.
Therefore, if she do the work herself, it would be faster. She'll earn $270 while $60 pays to Lawrence.
However, if she doesn't hire him then she'll lose out a complete amount of $270 if she doesn't take the more architectural jobs.
Hence, it is advisable that Lawrence should be hired at the $20 per hour wage rate.