1. (a) 100 cm (b) 16.7 cm, behind mirror, erect, m=2/3
2. (a) .264 W/cm^2 (b) .227 (c) 0
3. (a) 37.5 cm, 2.67D (b) 60 cm to left of 2nd lens, m=-3, virtual
4. (a) 6 cm (b) 4.5 cm (c) 48 degrees