Word problem - with confusing phrasing

Last week, Dolly bought x kg of grade B coffee powder for $12. If she bought grade A coffee powder instead, she would get 200 g less for $12. This week, the price of coffee powder for both grades increased by $5.00 per kg. If Dolly buys grade A coffee powder instead of grade B coffee powder, she will get 120 g less for $12.

Find how much grade B coffee powder Dolly bought last week.

I am thinking on the lines of quantity for week 2 x unit price for week 2 = 12 will yield a quadratic equation to solve.

But, I am confused with the second half of the problem. Does the 120 g less mean that she will get grade A coffee less that grade A for previous week or less that grade B this week?

Thanks for your help.

Edit: Sorry forgot the question part!