I am better at substitution, but you want to get the equations as similar as possible, but are the opposite, so you can cancel it out.
There are 3 vowels out of 11 letters in the word CANDLESTICK.
Probability (vowel) = 3/11
P( N or S) = 2/11 ( as there is 1 S and 1 N in the word)
P(not C) = 1 - P(picking a C) = 1 - 2/11 = 9/11 (note there are 2 C's in the word)