gistfile1.rb

# http://mozy.com/contest
# Question 4
# chendo's solution
require 'benchmark'

year = 0
fibs = [2, 0, 0, 0, 0] # age 0, 1, 2, 3, 4
adults = 0 # age > 5

Benchmark.bm do |bm|
  bm.report do
    
    while year < 75000
      year += 1
      fibs.unshift(adults += fibs.pop)
    end
    
    puts "At #{year} years, there would be #{adults + fibs.inject(0) { |mem, i| mem += i }}"
  end
end

#       user     system      total        real
# At 75 years, there would be 1457183502
#   0.000000   0.000000   0.000000 (  0.000675)