how to ruby plx

#Author:Zachary Williams
#Date: 10-1-12 19:57
#Chain of Command ROTC study guide

#titles array
t=["The President of the United States","Vice President of the United States","Secretary of State","Secretary of Defense",
    "Secretary of the Navy","Chairman, Joint Chiefs of Staff","Chief of Naval Operations","Commandant of the Marine Corps",
    "Master Chief Petty Officer of the Navy","Sergeant Major of the Marine Corps","Commander of Naval Education and Training Command",
    "Commander of Naval Service Training Command","NJROTC Area 12 Commander","Senior Naval Science Instructor","Naval Science Instructor"]
#names array
n=["The Honorable Barack Obama","The Honorable Joseph Biden","The Honorable Hillary Clinton","The Honorable Leon Panetta",
    "The Honorable Ray Mabus","General Martin Dempsey","Admiral Jonathan Greenert","General James Amos",
    "Master Chief Petty Officer Michael Stevens","Sergeant Major Michael Barrett","Rear Admiral Donald Quin","Rear Admiral David Steindl",
    "Commander Rusty Hibbard","Captain William Wilkerson","First Sergeant Lorenzo Cox"]
#used array
u=[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]
#score, set to 0 at beginning of each play through
score=0

def PickPerson
    getPerson=rand(15)
    CheckUsed(getPerson)
end

def CheckUsed(num)
    picks=0
    if num == 0
        picks=0
        Quiz(num)
    else
        PickPerson
        picks=picks+1
        if picks >= 15
            puts "You have answered all the questions!"
            FinalScore(score)
        end
    end
end

def Quiz(num)
    puts "Who is your " + t[num] + "?"
    print "Answer: "
    while tries <= 3
        answer=gets.chomp
        if answer == n[num]
            puts "Correct! +10 pts"
            QuizScore
        elsif answer == "exit"
            break
        else
            tries=tries+1
        end
    end

end

def QuizScore
    score=score+1
    PickPerson
end

def FinalScore(s)
    finalScore=s*10
    print "Your final score is "
    return finalScore
end

PickPerson()