I need this explained to me for information retrieval

Consider a corpus of 150,000 documents. Each document contains about 75 tokens. On aver age, each token (including spaces and punctuation) requires 5 bytes of storage. Furthermore assume that there are 75,000 distinct terms across all documents. Answer the following: O How much storage is required to store the document corpus? O What is the size of the term-document incidence matrix? O What is the maximum number cells in the matrix that can have a value of 1? O What percent of cells in the matrix have a value of 0