Aaron's solution

Gemfile

@@ -1,4 +1,4 @@
 source 'https://rubygems.org'
 
 gem 'rubocop', require: false
-gem 'rspec'
+gem 'rspec'

gem_city.rb

@@ -0,0 +1,47 @@
+# This class represents the town of GemCity
+# This is a town riddled with crime but we can find out how happy the town is
+class GemCity
+  attr_reader :population
+
+  def initialize
+    @people = {  thieves: 5, Officers: 1 }
+    @population = 50
+  end
+
+  def thieves(thieves_number = @people[:thieves])
+    @people[:thieves] = thieves_number
+  end
+
+  def officers
+    @people[:Officers]
+  end
+
+  def officers=(officers)
+    @people[:Officers] = officers
+  end
+
+  def happiness_of_town
+    # happiness is random... people don't know what they want!
+    happiness_vals = []
+    happiness = 0
+    (1..@population).each do
+      happiness_vals.push(rand((100 - successful_crime_rate)..100))
+    end
+    happiness_vals.each do |value|
+      happiness += value
+    end
+    happiness / 100
+  end
+
+  def successful_crime_rate
+    thieves = @people[:thieves]
+    officers = @people[:Officers]
+    if thieves <= 0 || officers > thieves
+      odds_percent = 0
+    else
+      odds = 1 - officers.to_f / thieves.to_f
+      odds_percent = odds * 100
+    end
+    odds_percent
+  end
+end

gem_city_spec.rb

@@ -1,5 +1,5 @@
 require 'rspec'
-require_relative 'GemCity' # This line may need to be changed
+require_relative 'gem_city' # This line may need to be changed
 
 describe 'Gem City' do
   let(:city) { GemCity.new }
@@ -16,7 +16,7 @@
 
     it 'officers = thieves' do
       city.thieves 1
-      city.setOfficers 1 # This line may need to be changed
+      city.officers = 1 # This line may need to be changed
       expect(city.successful_crime_rate).to eq(0)
     end
 
@@ -27,7 +27,7 @@
 
     it 'officers > thieves' do
       city.thieves 1
-      city.setOfficers 2 # This line may need to be changed
+      city.officers = 2 # This line may need to be changed
       expect(city.successful_crime_rate).to eq(0)
     end
   end