Answer:
Step-by-step explanation:
See the attachment for derivation of the equation.
y = -(6/7)x + 20 6/7
The y-intercept of the equation is 20 6/7, which means there is 20 6/7 hours of setup time required. When Anna arrives, she has not yet done any setup, so she would not have done any work yet.
In any event, the graph does not tell us how much time Anna really worked. Did Anna spend 6 or 9 hours on the setup? We don't know.