diff --git a/src/ticket/audience.ts b/src/ticket/audience.ts
index fb285f2..3d9ebfa 100644
--- a/src/ticket/audience.ts
+++ b/src/ticket/audience.ts
@@ -1,13 +1,10 @@
 import { Bag } from './bag';
+import { Ticket } from './ticket';
 
 export class Audience {
-  private readonly bag: Bag;
+  constructor(private bag: Bag) {}
 
-  constructor(bag: Bag) {
-    this.bag = bag;
-  }
-
-  get getBag(): Bag {
-    return this.bag;
+  buy(ticket: Ticket): number {
+    return this.bag.hold(ticket);
   }
 }
diff --git a/src/ticket/bag.ts b/src/ticket/bag.ts
index 8942c71..04199b4 100644
--- a/src/ticket/bag.ts
+++ b/src/ticket/bag.ts
@@ -2,16 +2,9 @@ import { Invitation } from './invitation';
 import { Ticket } from './ticket';
 
 export class Bag {
-  private amount: number;
-
-  private invitation: Invitation;
-
   private ticket: Ticket;
 
-  constructor(invitation: Invitation, amount: number) {
-    this.invitation = invitation;
-    this.amount = amount;
-  }
+  constructor(private invitation: Invitation, private amount: number) {}
 
   public hasInvitation(): boolean {
     return this.ticket != null;
@@ -28,4 +21,16 @@ export class Bag {
   public plusAmount(amount: number) {
     this.amount += amount;
   }
+
+  public hold(ticket: Ticket) {
+    if (this.hasInvitation()) {
+      this.setTicket(ticket);
+      return 0;
+    }
+
+    this.setTicket(ticket);
+    this.minusAmount(ticket.getFee);
+
+    return ticket.getFee;
+  }
 }
diff --git a/src/ticket/theater.ts b/src/ticket/theater.ts
index 3a9f48c..21d6e8e 100644
--- a/src/ticket/theater.ts
+++ b/src/ticket/theater.ts
@@ -2,21 +2,9 @@ import { Audience } from './audience';
 import { TicketSeller } from './ticketSeller';
 
 export class Theater {
-  private ticketSeller: TicketSeller;
-
-  constructor(ticketSeller: TicketSeller) {
-    this.ticketSeller = ticketSeller;
-  }
+  constructor(private ticketSeller: TicketSeller) {}
 
   public enter(audience: Audience): void {
-    if (audience.getBag.hasInvitation()) {
-      const ticket = this.ticketSeller.getTicketOffice.getTicket;
-      audience.getBag.setTicket(ticket);
-    } else {
-      const ticket = this.ticketSeller.getTicketOffice.getTicket;
-      audience.getBag.minusAmount(ticket.getFee);
-      this.ticketSeller.getTicketOffice.plusAmount(ticket.getFee);
-      audience.getBag.setTicket(ticket);
-    }
+    this.ticketSeller.sellTo(audience);
   }
 }
diff --git a/src/ticket/ticketOffice.ts b/src/ticket/ticketOffice.ts
index c39c74a..8a1aeb1 100644
--- a/src/ticket/ticketOffice.ts
+++ b/src/ticket/ticketOffice.ts
@@ -1,14 +1,7 @@
 import { Ticket } from './ticket';
 
 export class TicketOffice {
-  private amount: number;
-
-  private tickets: Array<Ticket>;
-
-  constructor(amount: number, tickets: Array<Ticket>) {
-    this.amount = amount;
-    this.tickets = tickets;
-  }
+  constructor(private amount: number, private tickets: Array<Ticket>) {}
 
   get getTicket(): Ticket {
     return this.tickets.pop();
diff --git a/src/ticket/ticketSeller.ts b/src/ticket/ticketSeller.ts
index 2cfe2f7..fb5f240 100644
--- a/src/ticket/ticketSeller.ts
+++ b/src/ticket/ticketSeller.ts
@@ -1,13 +1,10 @@
 import { TicketOffice } from './ticketOffice';
+import { Audience } from './audience';
 
 export class TicketSeller {
-  private readonly ticketOffice: TicketOffice;
+  constructor(private ticketOffice: TicketOffice) {}
 
-  constructor(ticketOffice: TicketOffice) {
-    this.ticketOffice = ticketOffice;
-  }
-
-  get getTicketOffice(): TicketOffice {
-    return this.ticketOffice;
+  sellTo(audience: Audience) {
+    this.ticketOffice.plusAmount(audience.buy(this.ticketOffice.getTicket));
   }
 }