Question 1127201

Hi Arnold!

in the following series of {{{w}}}, {{{s}}}, {{{p}}}, {{{l}}}, {{{h}}} what would be the next letter? 

This is more a puzzle than it is a problem in mathematics.
That being the case you need to look at the pattern in the series.

All letters in the series are consonants. The pattern is that every other letter following it will be a consonant.

if you go backward:
 
4th consonant before the {{{W}}}  is letter {{{S}}}
3th consonant before the {{{S}}}  is letter {{{P}}} -> because 4th letter is vowel
4th consonant before the {{{P}}} is letter{{{ L}}}
4th consonant before the {{{L}}} is letter {{{H}}}
4th consonant before the {{{H}}} is letter {{{highlight(D)}}}-> your answer

so, you have {{{W}}}, {{{S}}}, {{{P}}}, {{{L}}}, {{{H}}},{{{highlight(D)}}}