Let t be the time in hours it takes a block of ice to melt at T degrees.
Since both variables have an inverse relation, we can say that:
Where alpha is a constant value.
Since we know that a block of ice melts in 2.5 hours when the temperature is 54 degrees, we can plug in such data and find alpha as following:
Therefore, our expression would be:
For T = 45,
We can conclude that it would take 3 hours for the block of ice to melt.