generally in algebra you will use the letter "x" to represent a value you do not know, so it wants an algebraic expression for "p subtracted from 115", this can be rewritten as 115 - p. So the unknown value "x" is equal to 115 - p.
It’s biased because he is asking people who left a country concert and usually people who go to concerts go because it’s the type of music that they like, so the chances of someone saying they like a different kind of music probably won’t happen.
