Mathematics have aided managers in decision making by providing a tools to make informed decisions. The book addresses two problems faced by a manager through cases. Case 1 deals with the problem of Targeting in the Segmenting Targeting and positioning. Many approaches to segmentation exist but few are available to help manager decide on which segments to target or rather which ones to avoid. Case 2 deals with the capital budgeting process i.e. selection of projects amongst many projects .The standard aids of capital budgeting are examined and a collaborative approach combing most of them is used to arrive at a decision on whether to invest in a project or not. Both cases use rough set theory to arrive at a quantifiable solution to aid in the decision making. Mrs. Darshana Pathak would like to thank her parents and family for their love and support, her husband Mr. Bharat Joshi for much needed encouragement. Mr. Jatin Pandey would like to thank his parents Mr. S.C. Pandey and Mrs. Hema Pandey for their love and support and his sister Miss. Nayna Garg for her encouragement and inputs throughout the completion of this book.