Pencil = 1 unit, pen = 4 units. The pencil is 48 g lighter, so the gap of 3 units is 48 g.

Pencil1Pen111148 g lighter = 3 units

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

  1. Pen − Pencil = 3 units → 48 g
  2. 1 unit (pencil) → 48 ÷ 3 = 16 g

The pencil is 16 g.

Check: pen 64 g − pencil 16 g = 48 g, and 64 = 4 × 16. ✓