Answer : The specific heat of the metal is, 
Explanation :
In this problem we assumed that heat given by the hot body is equal to the heat taken by the cold body.


where,
= specific heat of metal = ?
= specific heat of water = 
= mass of metal = 75 g
= mass of water = 
= final temperature of mixture = 
= initial temperature of metal = 
= initial temperature of water = 
Now put all the given values in the above formula, we get
![(75g)\times c_1\times (25-100.0)^oC=-[(80.0g)\times 4.18J/g^oC\times (25-20.0)^oC]](https://tex.z-dn.net/?f=%2875g%29%5Ctimes%20c_1%5Ctimes%20%2825-100.0%29%5EoC%3D-%5B%2880.0g%29%5Ctimes%204.18J%2Fg%5EoC%5Ctimes%20%2825-20.0%29%5EoC%5D)

Therefore, the specific heat of the metal is, 