The revenue function $R(x)$ is found by multiplying the price per unit $p(x)$ by the number of units sold $x$.

The demand function, which gives the price per unit, is $p = D(x) = 41 - 0.3x$.

Thus, the revenue function is:

$R(x) = x \cdot p(x)$

Substitute $p(x) = 41 - 0.3x$ into the equation:

$R(x) = x \cdot (41 - 0.3x)$

Simplify the expression:

$R(x) = 41x - 0.3x^2$

So, the revenue function is:

$R(x) = 41x - 0.3x^2$

Would you like further details or have any questions?

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Here are 5 related questions to explore further:

1. How do we find the profit function using the revenue and cost functions?
2. At what value of $x$ is the revenue maximized?
3. What is the marginal revenue function for this problem?
4. How do changes in price affect the revenue function?
5. How do you find the break-even point using the cost and revenue functions?

Tip: The maximum revenue typically occurs where the derivative of the revenue function equals zero, as this finds the critical points for maximization.