#### Answer

The mass of the water in the pool is $1.44\times 10^5~m^3$

#### Work Step by Step

Note that the average depth of the water in the pool is 2.0 meters. We can find the volume of the water in the pool;
$V = (6.0~m)(12.0~m)(2.0~m)$
$V = 144.0~m^3$
We can find the mass of the water in the pool:
$M = \rho~V$
$M = (1.00\times 10^3~kg/m^3)(144.0~m^3)$
$M = 1.44\times 10^5~m^3$
The mass of the water in the pool is $1.44\times 10^5~m^3$.