Question

Round to the nearest gram

Answer 1

Alright, so after a half-life, half of the previous number would be left. So basically,

180 g ← 0 half lives

90 g ← 1 half life

45 g ← 2 half lives

22.5 g ← 3 half lives

11.25 g ← 4 half lives

Therefore, the answer is 11.25 grams