The image you uploaded shows a question about a linear demand function for a specific type of cell phone. Here's a breakdown of the relevant parts:

Part (a):

• The demand function is given as $q(p) = -10p + 4390$, where $p$ is the price in dollars, and $q(p)$ represents the sales in millions of phones.
• You're asked to predict the sales if the price is raised to $385.

We can use the given linear equation to calculate the predicted sales: $q(385) = -10(385) + 4390$

Let me calculate this for you.The predicted sales for this type of cell phone when the price is raised to $385 is 540 million phones.

Part (b):

• You're asked to fill in the blank: For every $1 increase in price, the sales of this type of cell phone decrease by 10 million units.
• This matches the slope of the linear demand function $-10$, meaning sales drop by 10 million units for each $1 increase in price.

Do you have any further questions or would you like more details on how this was calculated?

Here are 5 related questions to deepen understanding:

1. How would the demand function change if the slope became steeper, say $q(p) = -15p + 4390$?
2. What is the price at which sales would drop to zero?
3. How would the sales be affected if the price dropped to $200?
4. Can you derive a revenue function from the given demand equation?
5. What assumptions are made about the demand for this phone model in creating a linear demand function?

Tip: In linear demand functions, the slope (rate of change in sales per price unit) is crucial in predicting consumer behavior. Understanding this helps in pricing strategies!