Answer
$x=5.94m$ from the left endpoint
$x=5.82m$ from the right endpoint
Work Step by Step
$F_L$ is force of left rope
$F_R$ is force of right rope
$F_P=39.2N$ is weight of paint
$F_S=245N$ is weight of scaffold
$F_M=637N$ is weight of man
Forces in the vertical direction must be balanced
$F_L+F_R=F_P+F_S+F_M=920N$
Calculate if man can stand on right end of scaffold. Pivot point is the left end.
$\sum\tau=F_L(1m)-F_P(2m)-F_S(3m)+F_R(5m)-F_M(6m)=0$
$F_R=929N$, which is not possible because $F_L\ge0$ since ropes can't push.
Calculate if man can stand on left end of scaffold. Pivot point is the right end.
$\sum\tau=-F_L(5m)+F_P(4m)+F_S(3m)-F_R(1m)+F_M(6m)=0$
$F_L=948N$, which is not possible because $F_R\ge0$ since ropes can't push.
Calculate where man can safely stand
Assuming $F_L=0$ and $F_R=920N$
$\sum\tau=-F_P(2m)-F_S(3m)+920(5m)-F_M(xm)=0$
$x=5.94m$ from the left endpoint
Assuming $F_R=0$ and $F_L=920N$
$\sum\tau=F_P(4m)+F_S(3m)-920(5m)+F_M(xm)=0$
$x=5.82m$ from the right endpoint
