Answer:
Choice B is correct; (10, 60)
Step-by-step explanation:
For Lisa to make a profit, the function R should assume a value greater than 0;
R > 0
We are to determine the interval of x values for which the above expression will be true.
From the graph, R(x) = 0 when x = 10. As x increases from 10 to 60, the value of R(x) remains positive, that is;
R(x) ≥ 0 for values of x in the interval (10, 60)
The domain that she should use in order to only model selling prices for which she will make a profit is thus;
(10, 60)