Ricky is 3 equal units; Mif is 1 unit. Take Ben’s 33 kg out of the 117 kg first, leaving Ricky + Mif = 4 units.

Mif?Ricky111Ben33 kg117 kg

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

  1. Ricky + Mif → 117 − 33 = 84 kg
  2. 4 units → 84 kg
  3. 1 unit → 84 ÷ 4 = 21 kg

Mif is 21 kg.

Check: 21 + 63 (Ricky) + 33 (Ben) = 117 kg. ✓