Convert all to centimetres first.<br><br>&bull; Total height = 6 m 52 cm = 652 cm<br>&bull; Average of Sam + wife = 1 m 67 cm = 167 cm<br>&bull; Sum of Sam + wife = 167 × 2 = 334 cm<br>&bull; Sum of 2 sons = 652 − 334 = 318 cm<br>&bull; Average height of 2 sons = 318 ÷ 2 = 159 cm<br><br>Final Answer: 159 cm