Rani appeared for an examination which had four papers, with the weightage of the four papers being in the ratio 1:2:3:x She secured 60 percent marks in Paper 1, 75 percent marks in Paper 2, 72 percent marks in Paper 3 and 80 percent in Paper 4. If the overall average scores of all the four papers taken together is 75.5 percent, what is the value of x?