Larry is twice as heavy as Peter. The difference in mass is 36 kg.<br><br>
[[model:questions/solutions/q10645.png]]<br><br>
Let Peter's mass = 1 unit, Larry's mass = 2 units.<br>
&bull; Difference = 2 units - 1 unit = 1 unit<br>
&bull; 1 unit → 36 kg<br>
&bull; Peter = 1 unit = 36 kg<br>
&bull; Larry = 2 units = 2 × 36 = 72 kg<br>
&bull; Total mass = 36 + 72 = 108 kg<br><br>
Check: Larry (72 kg) is twice Peter (36 kg), and 72 - 36 = 36. ✓<br><br>
Final Answer: D: 108 kg