need help with a program

[windecks]

This program gives you the option of picking 3 different rental cars. Jeep Wrangler which cost $55 per day, Grand Cherokee which cost $85 per day, and a Land Rover which cost $125 dollars per day. You also have an option to refill the gas for $52. The program needs to calculate the total cost.

here my code, but its didnt work:

Private Sub Command1_Click()
Dim sngWrangler As Single, sngGrand As Single
Dim sngTotal As Single, sngRover, sngDays As Single
 
'assighn the variables
sngDays = cboDays.Text
'make calculations
sngTotal = (sngWrangler * sngDays) + (sngGrand * sngDays) + (sngRover * sngDays)
'display the results on the screen
lblTotal.Caption = sngTotal
 
End Sub
 
Private Sub Form_Load()
cboDays.AddItem 1
cboDays.AddItem 2
cboDays.AddItem 3
cboDays.AddItem 4
cboDays.AddItem 5
cboDays.AddItem 6
cboDays.AddItem 7
 
End Sub
 
Private Sub optRover_Click()
If optRover.Value = True Then
    sngRover = 125
Else
    sngRover = 0
End If
End Sub
 
Private Sub optWrangler_Click()
If optWrangler.Value = True Then
    sngWrangler = 55
Else
    sngWrangler = 0
End If
End Sub
 
Private Sub optGrand_Click()
If optGrand.Value = True Then
    sngGrand = 85
Else
    sngGrand = 0
End If
End Sub
 
Private Sub chkGas_Click()
 
If chkGas.Value = 1 Then
    sngGas = 52
Else
    sngGas = 0
End If
 
lblTotal.Caption = ""
End Sub