VS 2010 If textbox value less than

Hi All,


If i have textbox1 "Number of people"

then textbox2 "Total Price"

but the price per person varies on the number of people.

eg.
If number of people less than 100 the price is 0.10 per person --- Total Price = Number of people * 0.10
If the number of people is equal to 100 or below 200 the price is 0.20 per person --- Total Price = Number of people * 0.20
If the number of people is equal to 200 or below 300 the price is 0.30 per person --- Total Price = Number of people * 0.30

can anyone help?

Thanks in advance
Chris