Answer: a) $33.98, b) $2245.05
Step-by-step explanation:
Since we have given that
Revenue function is given by

On simplifying, we get that

If the number of units sold = 65
We need to find the Marginal revenue.
Revenue at 65 units would be

Revenue at 66 units would be

So, marginal revenue would be

Projected revenue from the sale of 66 units would be
Hence, a) $33.98, b) $2245.05