Explanation:

Let the earnings of a man be x and that of a woman be y.

From the eqn (i) and (ii), we get x = 24 and y = 27
∴ Earnings of six men and five women = 6 × 24 + 5 × 27 = 144 + 135 = 279
∴   Number of days = 1116 /279 = 4 days