Brother = 8 &times; Baby girl. The model shows girl as 1 unit and brother as 8 units.<br><br>&bull; Baby girl = 4 kg (1 unit)<br>&bull; Brother = 8 &times; 4 = 32 kg<br>&bull; Difference = 32 &minus; 4 = 28 kg<br><br>Her brother is 28 kg heavier than her.<br>Check: 4 &times; 8 = 32 kg. &#10003;