Final answer:
The manager should wait a number of weeks determined by solving the quadratic equation – resulting from the increase in yield and decrease in price over time – to ensure the revenue per tree is $42.
Step-by-step explanation:
To determine how many weeks the manager of a cherry orchard should wait to get an average revenue of $42.00 per tree, we need to establish an equation that models the revenue per tree over time. Initially, we have a yield of 100 lb per tree, selling at 50 cents per pound, which gives us a revenue of $50 per tree.
Each week, the yield increases by 8 lb, and the price decreases by 4 cents per pound. If w represents the number of weeks waited, the yield becomes (100 + 8w) lb, and the price becomes (50 - 4w) cents per pound. The revenue R, in dollars, is calculated by the formula R = (yield) × (price), thus R = (100 + 8w) × (0.50 - 0.04w).
To find w when the revenue is $42 per tree, we set the revenue formula equal to 42 and solve for w:
42 = (100 + 8w) × (0.50 - 0.04w).
Expanding and simplifying the equation, we get:
42 = 50 - 0.04w + 0.50 × 8w - 0.04 × 8w²,
This is a quadratic equation that can be simplified to 0 = -0.32w² + 4w + 8. Using the quadratic formula or factoring, we solve for w to find the number of weeks the manager should wait.