Linear Programming (problem)

[vin17]

Any help is greatly appreciated...

There are three 'nutrients': A, B and C

The minimum amount of units required of each are 160, 200 and 80 respectively.

There are two brands of products containing these nutrients...
Product Alpha costs $8/bag and contains 3 units of A, 5 of B and 1 of c.
Product Beta costs $6/bag and contains 2 units of A, B and C each.

In order to minimize costs while still maintaining the amount of nutrients, what combination of Alpha and Beta should be purchased (you do not need to solve it, only construct the math model ie. objective function and constraints).

Edit: I have already done similar questions with the exception that there wasn't multiple products and prices involved.