A teacher filled the squares of a chequered table with
Eight schoolchildren solved
If each problem is solved by
Is it possible to arrange natural numbers from 1 to
A cinema contains 7 rows each with 10 seats. A group of 50 children went to see the morning screening of a film, and returned for the evening screening. Prove that there will be two children who sat in the same row for both the morning and the evening screening.