Solution:Total time, From Thursday 4 : 00 am to Friday 8 : 30 pm = 40 hour 30 minutes
According to the question,
Clock gains in 3 hours = 20 seconds
Since clock gains 270 seconds So time is 8 : 30 PM + 270 seconds = 8 : 30 PM + 4 minute and 30 second
Hence it will become 8 hours 34 minutes and 30 seconds PM.