Answer: [tex]40^{\circ}C[/tex]
Explanation:
Given
Coldwater is at [tex]5^{\circ}C[/tex]
Hot water is at [tex]75^{\circ}C[/tex]
Suppose an equal amount of water is mixed i.e. m
So, the heat released by hot water is equal to the heat gained by cold water and the final common temperature be T
[tex]\Rightarrow mc(75-T)=mc(T-5)\\\Rightarrow 75-T=T-5\\\Rightarrow 2T=80\\\Rightarrow T=40^{\circ}C[/tex]
Option (2) is correct