Give an example of two permutations of the same n labels 0; 1; : : : ; n 1 that cannot be inorder and postorder traversal lists of the same binary tree.

The amount spent on food and drink by 20 customers is shown below what is the modal amount spent and the median? 40 25 8 36 18 15 24 27 43 9 12 19 22 34 31 20 26 19 17 28