cual es el valorde la razón de cambio cuando metemos un vaso de agua al tiempo al congelador por 15 minutos

The clearer rendering reads;

"What is the value of the rate of change when we put a glass of water in the freezer for 15 minutes".

What is generally accepted is that at a temperature of 0° Celsius (32° Fahrenheit) water freezes.

Thus, if after 15 minutes the temperature of the water inside the freezer hasn't gotten to 0° Celsius then there is no change of state from liquid to solid.