Nilan wrote the following expression in his note book:
\(3b(5b^{4} - 2b + 8) = 15b^{4} - 6b + 24b\)
His teacher marked the above expression as incorrect.
Based on the situation, answer the following questions.
1. What should be the correct expansion of \(3b(5b^{4} - 2b + 8)\)?
2. What error did Nilan make while multiplying the expressions?
3. Which rule of exponents should he use to rectify his mistake?
4. What is the degree of the correct expansion?