Answer :
Answer: 25 books.
Step-by-step explanation:
Let as consider we need to find "how many books did Mr. Wharton buy in all?"
Let total number of books bought by Mr. Wharton be x.
80% of all the books she bought were paperbacks.
[tex]Paperbacks=x\times \dfrac{80}{100}=0.8x[/tex]
It is given that the number of paperbacks is 20.
[tex]0.8x=20[/tex]
Divide both sides by 0.8.
[tex]x=\dfrac{20}{0.8}[/tex]
[tex]x=25[/tex]
Therefore, Ms Wharton bought 25 books in all.