How many characters does the largest word from this list contain?Try 'waysliding', which has 10 characters.
How many viable words are possible to make using the specified combination?There are 3 words you're able to choose for words that start with 'w' and include 'sli'.
What is the highest scoring word you can play in Scrabble ?Since there are only 3 combinations possible, your only feasible word is 'withslip' scoring 16 points.