Question 25
A poem can have any number of lines and each line may rhyme with any of the other lines.
For poems with only two lines, there are two different rhyming structures: either the lines rhyme or they do not.
For poems with three lines, there are five different rhyming structures: either all three lines rhyme, exactly one pair of lines rhyme (occurring in three ways), or none of the lines rhyme.
How many different rhyming structures are there for poems with four lines?
For poems with only two lines, there are two different rhyming structures: either the lines rhyme or they do not.
For poems with three lines, there are five different rhyming structures: either all three lines rhyme, exactly one pair of lines rhyme (occurring in three ways), or none of the lines rhyme.
How many different rhyming structures are there for poems with four lines?