At every 15° change in longitude, time will change by an hour. So, difference of longitude between Perth and Los Angeles is 118+ 110 = 228. Now, to calculate change in hour, 228/15 = 15 h 12 min. Now, in order to know the timing in Los Angeles, these 15 h 12 min will be subtracted from 6 am, so finally answer will be 2.48 pm December 31.