I can only give a approximated guide on the subject! I don't know the variation of the pigs in different country's. And what feeds would be used to gain this weight.
Firstly I have talked before, you want to get pigs at around 8-10 weeks of age, after they have been properly weaned. (One month seems young, too soon).
Secondly The growth weight at 4 months would be around 70kg. To get the maximum market weight 6 months 110kg.
The way to achieve this by the feeding - So at around 9 weeks old the pig will be eating about 1kg of feed per day, then at 14 weeks an increase to 2kg per day.
You can then bulk feed him for the last month, of under 4kg per day to get the maximum weight.
Using this guide you should achieve the following - 10 weeks the pig will be about 30kg and at 18 weeks around 80kg.
Per Pig 200kg of life time food.
So in Cambodia the price of the Piglet $40. Sale of the Pig $200. Profit $160. Less food, housing, medicines.