A committee of 4 persons can be formed in following ways (i) 3 persons and one ladies =‌7C3×‌3C1=35×3=105 (ii) 2 persons and two ladies =‌7C2×‌3C2=21×3=63 (iii) 1 person and three ladies =‌7C1×‌3C3=7×1=7 ∴ Total number of ways =105+63+7=175