How to add to the number near the end of each line

Question

Suppose there is some text from a file:

(bookmarks
("Chapter 1 Introduction 1" "#1"
("1.1 Problem Statement and Basic Definitions 2" "#2")
("1.2 Illustrative Examples 4" "#4")
("1.3 Guidelines for Model Construction 26" "#26")
("Exercises 30" "#30")
("Notes and References 34" "#34"))
)

How can I add 11 to the last number in each line if there is one, ie

(bookmarks
("Chapter 1 Introduction 1" "#12"
("1.1 Problem Statement and Basic Definitions 2" "#13")
("1.2 Illustrative Examples 4" "#15")
("1.3 Guidelines for Model Construction 26" "#37")
("Exercises 30" "#41")
("Notes and References 34" "#45"))
)

by using sed, awk, python, perl, regex ....

Thanks and regards!

Answer 1

awk -F'#' 'NF>1{split($2,a,"[0-9]+");print $1 FS $2+11 a[2];next}1' infile

Proof of Concept

$ awk -F'#' 'NF>1{split($2,a,"[0-9]+");print $1 FS $2+11 a[2];next}1' infile
(bookmarks
("Chapter 1 Introduction 1" "#12"
("1.1 Problem Statement and Basic Definitions 2" "#13")
("1.2 Illustrative Examples 4" "#15")
("1.3 Guidelines for Model Construction 26" "#37")
("Exercises 30" "#41")
("Notes and References 34" "#45"))
)