Answer:
208.7°C was the initial temperature of the limestone.
Explanation:
Heat lost by limestone will be equal to heat gained by the water

Mass of limestone = 
Specific heat capacity of limestone = 
Initial temperature of the limestone = 
Final temperature =
=T = 51.9°C

Mass of water= 
Specific heat capacity of water= 
Initial temperature of the water = 
Final temperature of water =
=T = 51.9°C



On substituting all values:


208.7°C was the initial temperature of the limestone.