ramon took a collection of colored tiles from a box. amelia took 13 tiles from his collection and keiko took half of those remaining. ramon had 15 tiles left.

Question

how many did he start with

Answer 1

Let's assume that Ramon started with "x" number of tiles.
Amelia took 13 tiles from Ramon's collection, leaving him with x - 13 tiles.
Keiko took half of those remaining tiles, which is (x - 13)/2.
Therefore, Ramon had 15 tiles left, so we can set up the equation: (x - 13)/2 = 15.
Multiplying both sides of the equation by 2 gives: x - 13 = 30.
Adding 13 to both sides of the equation gives: x = 43.
Therefore, Ramon started with 43 tiles. Answer: \boxed{43}.