The question here might have an error in terms of the phrasing. The phrasing here suggests that number of tiles in P increased by 3 times in original, meaning that the total tiles in P at the end should be 4x. If your approach was this way, your answer would be x=24.47(2 d.p.), a=195.76, b=147.88, c= 17.88. However, I believe that the question may be looking for a whole number answer instead, so you could round off the above answers instead to get: x=24, a=196, b=148, c=18. Otherwise, you can take the above interpretation that the amount in P tripled instead. The steps to solve the problem is the same, just different interpretation of the question. The workings are also for your understanding, so you do not have to do the same in your examinations. Hope this helps!