Carpet Calculator - Rolls Required To Cover Room?

I'm trying to make a carpet calculator that will do the following:
1) How many metres of carpet are needed to cover a room.
2) How many rolls of carpet that will be.
3) How much full-width carpet will be left on the last roll.

The carpet is supplied in rolls that are 5 meters wide and 30 metres long. Any excess width is discarded. This means that rooms that are wider than 5 meters need several strips of carpet. The smallest space that will be carpeted is 1m x1m, the biggest is 20m x 20m. I only need whole meter lengths, so example if only 1.6meters of carpet were used to cover a room it would be rounded to 2 meters.

Here's the code that's giving me incorrect calculations. The number of rolls required to carpet the room seems to be the biggest miscalculation.
Private Sub btnCalculate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCalculate.Click
Dim width, length As Single 'Defines variables.
If IsValidInput(txtWidth.Text) Then
width = txtWidth.Text
[Code] .....