C is not possible to be 8 as 58 is not divisible by 4.
By considering the combination,225 = 3²×5²：3×3 = 9255 = 3×5×17：2×2×2 = 8...
已 updated, thanks
thanks a lot, 我都覺得我的方法好慢，原來真係有更快的方法多謝您。
不用謝：)請問這三題會否上傳至 Youtube ?
可能會，之後拍 HKMO 時可能會再做一次呢題
Consider the condition (d) which implies that CBA must be a perfect square number. (Factors are in pairs, only exception is a square number. Odd number of factors imply which is a perfect square)Obviously, A=5. There are only two square numbers 15^2=225 and 25^2=625 which are in between 100-999. As only 2+2+5=3*3, CBA=225 and ABC=522