Given that the painter took three days to paint the exterior of the house in the following timings.
Thursday         7.30 am to 5.15 pm  = 9 hours 45 minutes
Friday              7.00 am to 4.40 pm  = 9 hours 40 minutes
Saturday          8.30 am to 4.30 pm = 8 hours  
Also, it is given that the rate 23 $ per hour, and there is a rest of 1/2 hour lunch break each day.
So total lunch break = 3 x 1/2 hours = 3/2 hours = 1.5 hours = 1 hour 30 minutes
Total working time = 9 hours 45 minutes + 9 hours 40 minutes + 8 hours  
                                = 27 hours 25 minutes
For 1 hour the rate is $ 23
1 hour = $ 23
60 minutes = $ 23
1 minute = $ 23/60
Now we have to subtract the lunchtime from the total time.
Then, 
Time for which he was paid = 27 hours 25 minutes - 1 hour 30 minutes
                                               = 25 hours 55 minutes
So, 
25 hours = $ 25 x 23 = $ 575
55 minutes = $ 55 x 23/60 = $ 21.08
Hence, the total money he was paid is  = $ 575 + $ 21.08 = $ 596.08 
Therefore the required answer is $ 596.08