Tension of rope

Two window washer works on a plank of mass 15 kg suspended by ropes that are tied to each end. The plank is a uniform piece of wood 4.0 meters wide. Person A has a mass of 75 kg and stands 0.5 m from the left side of the plank. Person B has a mass of 60 kg and stands 1.0 m from the right side of the plank. The maximum tension either rope can support before it breaks is 900 NWhat is the tension in each rope.How much closer can washer B get to the left end before one of the ropes breaks.