Answer:
A) Eight
Step-by-step explanation:
Since Brenda is a price taker, she will be able to hire bricklayers as long as her marginal revenue product (MRP) is higher than her marginal cost of hiring another bricklayer.
A bricklayer's wage per hour is $18.00:
- the first seven bricklayers provide a MRP of $22.25 which is larger than $18.00
- the eighth bricklayer provides a MRP of $18.50 which is still larger than $18.00
- but the ninth bricklayer provides a MRP of $17.75 which is lower than $18.00, so she shouldn't hire the ninth bricklayer.