Set up an equation to solve this problem. Suppose Bob delivers x papers, then Amy delivers 2x papers, Celine delivers (2x-12) papers, according to the information in the problem. The number of papers delivered in total in 128, therefore x+2x+(2x-12)=128, x=28. Substitute x=28 in 2x-12, Celine delivered 2*28-12=44 papers.