Word Problems 2 Spacely's Sprockets, Heat problem, Socks

1.) Mr. Spacely has been rethinking the company's shipping schemes. As an employee for Spacely's Sprockets, Spacely has asked you to write a quick program that will be used to determine shipping costs.
A total purchase of items totaling under $50, we charge $5 shipping.
A total purchase of items totaling $50 and over, there is no shipping charge.

 Public Class Form1  
   Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click  
     'Declare variables  
     Dim purchase, shipping, total As Double  
     purchase = CDbl(txtpurchase.text)  
     shipping = 5  
     'Calculate total  
     If purchase >= 50 Then  
       total = FormatCurrency(purchase)  
     ElseIf purchase < 50 Then  
       total = purchase + shipping  
     End If  
     'Display total  
     MessageBox.Show("Your total is: " & FormatCurrency(total), "Please Pay")  
   End Sub  
 End Class  

2.) You are looking for something to control your heat in your apartment and you discover there is NOT an app for that. It's about time that someone created one. You decide that you are the one to do it. Here's what you want to do.
-You want to turn the heat on when the temp has dropped below 72
-You also want to turn the AC on when the temp gets above 76
Your app should display in a message box if the heat is on, the AC is on, or if the system is idle.

 Public Class Form1  
   Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click  
     'Declare variables  
     Dim temp As Double  
     temp = CDbl(txtpurchase.Text)  
     'Calculate total  
     If temp <= 72 Then  
       MessageBox.Show("The heat is on.", "Heat")  
     ElseIf temp > 72 And temp < 76 Then  
       MessageBox.Show("The system is idle", "Idle System")  
     ElseIf temp >= 76 Then  
       MessageBox.Show("The A/C is on.", "A/C")  
     End If  
   End Sub  
 End Class  

3.) You are working on a clothing website where people can buy kids socks. It's really hard for the customers to know what size they should buy for what age. It would be a good idea for the customer to have a tool to input their child's age and have the website suggest a size for them. Write a tool where you can set the age as a variable and have it suggest on of the sizes below:
a.0-2 yrs -XS
b.3-4 yrs -S
c.5-8 yrs -M
d.9-12 yrs -L
e.13+ yrs -XL

 Public Class Form1  
   Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click  
     'Declare variables  
     Dim age As Double  
     age = CDbl(txtpurchase.Text)  
     'Calculate total  
     If age <= 2 Then  
       MessageBox.Show("Your child's size is XS.", "XS")  
     ElseIf age >= 3 And age <= 4 Then  
       MessageBox.Show("Your child's size is Small", "Small")  
     ElseIf age >= 5 And age <= 8 Then  
       MessageBox.Show("Your child's size is Medium", "Medium")  
     ElseIf age >= 9 And age <= 12 Then  
       MessageBox.Show("Your child's size is Large", "Large")  
     ElseIf age >= 13 Then  
       MessageBox.Show("Your child's size is X-Large.", "X-Large")  
     End If  
   End Sub  
 End Class