Question

the weight of 7book is9kg how many such book weight 6kg

Answer 1

the question is wrong because the amount of change is there

Answer 2

Weight of 7 books = 9kg so number of books in 1 kg = 7/9 So no. Of books in 6 kg = 7/9 × 6 = 4.66 books which is not possible hence the question is wrong