STEP - BY - STEP EXPLANATION
What to find?
An expression for the total number of books.
Given:
Number of shelves = 5
Number of books in each shelf = k
If Lucy has a bookcase with 5 shelves and each of this
shelf has k books, then the total number of books can be determine by multiplying the numbers of book by the numbers of shelves.
That is;
[tex]\begin{gathered} Total\text{ number of book=5}\times k \\ \\ =5k \end{gathered}[/tex]
ANSWER
5K
