Maths Prelim

Haiz. Today's Maths was so damn difficult*, did the papar back to front. One advantage, the harder questions (the ones with more marks and lesser marks does not mean easy, can be harder than the ones 5 marks) if you do them first, as they carry more marks, you will pay more attention to them as you can concentrate better and make less careless mistakes, moreover, if you don't have time to finish some questions, the questions you haven't finished will be those which carry lesser maks.
THen there was one question the 2nd last one. That was the one which really racked my brains. I think it goes like this: Uncle Sunny had only Roses and Orchids in his nursery. There were 520 more orchids than roses. In July, he bought some more orchids and the number of orchids increased by 20%. He then sold some roses and the number of roses decreased by 10%. In the end, there were 2052 plants in his nursery, how many orchids did he have in June?
For this question, I used the most low-class method (not that im high classy) to solve it: Guess and Check. Lucky! Took only about 5 or 6 guesses to solve it! I think the answer is 1200? If I'm wrong, please correct me on the 'Chatterbox'. Thanks. -.-
*Say difficult to parents so if you do badly, they won't blame you, although some do, and if you do well, they will have a pleasent surprise. If you say its easy, the result most likely will turn out the wrong way, although sometimes it dosen't, and parents will scold you or cane you for doing badly, and if you score high marks, they would not be surprised!