A ladder, 5.0 m long, leans against a frictionless wall at a

Question

point 4.0 m above the ground. A painter is climbing up the
ladder. The mass of the ladder is 12.0 kg and the mass of the
painter is 60.0 kg.
The ladder begins to slip at its base when the painter is 70 %
of the way up the length of the ladder. What is the coefficient
of static friction between the ladder and the floor?
(The base of the ladder is 3 meters from the wall)