Given that the mass of water is m1 = 500 mL at temperature T1 = 10 degrees C.
The mass of water is m2 = 100 mL at temperature T2 = 70 degrees C
We have to find the final temperature of the water mixture.
The formula to find the final temperature of the mixture is
[tex]T_f=\frac{(m1T1+m2T2)}{(m1+m2)}[/tex]Substituting the values, the final temperature of the water will be
[tex]\begin{gathered} T_f=\frac{(500\times10)+(100\times70)}{(500+100)} \\ =20^{\circ}\text{ C} \end{gathered}[/tex]Thus, option (b) is correct.
