Answer
The amount of water that overflows is $16.2~cm^3$
Work Step by Step
We can find the original volume:
$V = (75.0~cm^2)(20.0~cm) = 1500~cm^2$
We can find the change in volume of the brass container due to the increase in temperature:
$\Delta V = \beta~\Delta T~V$
$\Delta V = (56\times 10^{-6}~K^{-1})(70.0~K)(1500~cm^3)$
$\Delta V = 5.88~cm^3$
We can find the change in volume of the water due to the increase in temperature:
$\Delta V = \beta~\Delta T~V$
$\Delta V = (210\times 10^{-6}~K^{-1})(70.0~K)(1500~cm^3)$
$\Delta V = 22.05~cm^3$
The amount of water that overflows is $22.05~cm^3-5.88~cm^3$ which is $16.2~cm^3$
