Let the number of book distributed in a day by a man = 5x
woman = 4x & child = 2x
Day 1 : There were 7 men, 5 women, 8 children
=> No. of books sold = (7 * 5x) + (5 * 4x) + (8 * 2x)
= 35x + 20x + 16x = 71x
Day 2 : There were 7 men, 3 women, 5 children [As, 2 women & 3 children were absent]
=> No. of books sold = (7 * 5x) + (3 * 4x) + (5 * 2x)
= 35x + 12x + 10x = 57x
Day 3 : There were 4 men, 5 women, 3 children [As, 3 men & 5 children were absent]
=> No. of books sold = (4 * 5x) + (5 * 4x) + (3 * 2x)
= 20x + 20x + 6x = 46x
Now, total books distributed on the course of three days = 71x + 57x + 46x = 2000
=> x = 2000/174
No. of books distributed on the second day = 57x = 57 * $\frac{2000}{174}$ = 655.17 = ~650