A group of students stood in three rows. The 1st row had 9s students. The 2nd row had 4s fewer students than the 1st row. The 3rd row had 7 more students than the 2nd row.
- Find the number of students in the 3rd row in terms of s. Give your answer in the simplest form.
- There were 42 students in the 3rd row. Find the value of s.