Question 557511
The hardest part of this question is the term each additional minute. If I make a call that's 10 minutes long, that'd be 1 minute plus 9 additional minutes. If my call was 15 minutes long, that'd be 1 minute plus 14 additional minutes. In general, its the flat rate minute, plus m-1 where m is the total number of minutes. 

As an equation we get:
9.50=.85+.27(m-1)
distribute the .27
9.50=.85+.27m-.27
combine like terms
9.50=.58+.27m
subtract .58 from both sides
8.92=.27m
divide both sides by .27
And we get 33.03
So that'd by 33 minutes