only first item in cart getting charged tax?

i charge based on shipping location. whenever someone puts more than one item in the cart, they only get charged tax on the first item... why?

example
20 blue boxes 8%tax price $10
30 red boxes 0%tax price $10

subtotal $20
tax $0.80
ups $2
total $22.80

what do i need to do to charge tax on all times in the shopping cart?

Never mind, I forgot to associate a tax code to that one particular product.