The solubility of a sparingly soluble salt AxBy, in water at 25°C = 1.4 × 10-4 M. The solubility product is 1.1 × 10-11. The possibilities are

Ksp=1.1×10−11=1.4×10−4x+yxx⋅yySo we have x + y = 3 (by comparing values). so, xx⋅yy=1.1×10−111.4×1.4×1.4×10−12=1101.96×1.4=4Hence x = 1,y = 2 or y = 1, x = 2.