Answer
The two mules together do $2.12\times 10^5~J$ of work on the barge.
Work Step by Step
We can find the work done by the two mules on the barge:
$Work = F~d~cos~\theta$
$Work = (2)(1000~N)~(150~m)~cos~45^{\circ}$
$Work = 2.12\times 10^5~J$
The two mules together do $2.12\times 10^5~J$ of work on the barge.
