Cosmetics take 1/7 = 1 unit. The remainder is 6 units; clothes are 5/6 of it = 5 units, leaving 1 unit. Clothes (5 units) exceed cosmetics (1 unit) by 4 units = $420.

Moneycosmetics 1uclothes 5uleft 1u

Plain numbers are given; italic underlined numbers are worked out.

  1. Clothes − cosmetics → 5 units − 1 unit = 4 units → $420
  2. 1 unit → $420 ÷ 4 = $105
  3. Money left → 1 unit = $105

Ms Pretty had $105 left.

Check: total 7 × $105 = $735; cosmetics $105, clothes $525, left $105; $525 − $105 = $420. ✓