Let

x = the price of the book

y = the price of the bookmark

A book and bookmark together sell for $10.10 means:

x + y = 10.10

The price of the book is $10.00 more than the price of the bookmark means:

x = y + 10

We need to solve the following system of equations:

x + y = 10.10

x = y + 10

........

Click here to see the step by step solution of the system of equations

........

x = $10.05

y = $0.05

The pice of the book is $10.05.

The price of the bookmark is $0.05 or 5 cents.