Ok lets make the number of chocolate bars Angelina bought be "C", and the amount of lollipops she bought be "L".
We know that she bought 12 items in total, so: L+C=12 (1) We also know that chocolate costs two dollars, and lollipops cost one dollar, so if she spent 16 dollars; 2C + 1L = 16 (2) We can subtract (1) from (2) so that: (2C + L) - (L + C) = 16 - 12 So C = 4 So she bought 4 chocolate bars. This also means she bought (12 - 4) lollipops, which is 8.
So Angelina bought 4 chocolate bars and 8 lollipops.