10)

11)

12)

13) (your answer is incorrect)

14) (your answer is incorrect)

15)

16)
-expression to represent this situation

Answer: In 1 group 57 students
/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
P.S. Hello from Russia :^)