As we know reading is a good habit and library give equal opportunity to all people by making books available to all. Reading books in a library has some cost, the same way Library ABC has some policies of taking and reading books that is a fixed charge for the first three days and an additional charge for each day thereafter. Following the same rules two students paid the library the following amount:

Shristi paid 27 for a book kept for seven days. While Bubbly paid 21 for the book kept for five days.​