In this case work is being done against gravity in lifting water. Now, the formula for calculating the work done against gravity is :
`W = m xx g xx h`
Here, Mass of water, m = 200 kg
Acceleration due to gravity, `g = 10 m//s^(2)`
And, Height, h = 6 m
Now putting these values in the above formula, we get :
`W = 200 xx 10 xx 6`
W = 12000 J
Thus, the work done is 12000 joules.