The total height of Sam, his wife and 2 sons is 6 m 52 cm. The average height of Sam and his wife is 1 m 67 cm. <br> If his elder son is 12 cm taller than his younger son, how tall is his elder son? <br> <input min="0" type="number" id ="imp5pg161q7b_1" class="lineinput" placeholder="?" /> cm