Problem$4.(\frac{25}{100})$

Block A is of mass $20$ kg and block B is of mass $5$ kg $.$ The coefficient of static friction between block B and the vertical wall and block A and the floor is ${}_{sl}=0\mathrm{.}30,$ and the coefficient of static friction between the two blocks $A$&$B$ is ${}_{s2}=0\mathrm{.}20.$ Determine the force P necessary for impending motion of block A $.$Can you answer this quwstion using vector triangles instead of sum of forces.