Can you post what you've tried so far?
Two blocks of masses M and m, are connected by a model string. Block m lies on a rough horizontal plane, and the coefficient of static friction between the block and the plane is . The string passes over a model pulley and the block M lies on a smooth plane that is inclined at an angle to the horizontal. The string is taut and the system is in equilibrium.
Model the blocks as particles and draw two force diagrams, choose appropriate co-ornate axes and express forces in terms of your unit vectors chosen.