Determine average length of the code

Question

Response to the following problem:

A source emits letters from an alphabet

A = (a₁,a₂,a₃,a₄,a₅) with probabilities P(a₁) =0.15 ,P(a₂) = 0.04,P(a₃) = 0.26,P(a₄) = 0.05, and P(a₅) = 0.50.

(a) Calculate the entropy of this source.

(b) Find a Huffman code for this source.

(c) Find the average length of the code in

(b) and its redundancy.