Question 218407
Let {{{n}}} = the number of band 
members in the shortest row
The next row will have {{{n + 2}}} band members
The next row will have {{{n + 2 + 2}}} band members
The fourth row will have {{{n + 2 + 2 + 2}}} band members
given:
There are {{{92}}} band members
{{{n + n + 2 + n + 4 + n + 6 = 92}}}
{{{4n + 12 = 92}}}
{{{4n = 80}}}
{{{n = 20}}}
The shortest row has 20 members