On the test, the teacher gave five problems and assigned a test grade equal to the number of problems solved. All students, except for Petya, solved the same number of problems, while Petya solved one more. The first problem was solved by 9 people, the second by 7 people, the third by 5 people, the fourth by 3 people, and the fifth by one person.

How many fours and fives were received on the test?
Suppose Petya scored no less than 4, then the others solved no less than 3 problems each, and the total number of problems solved by all students is no less than $3 \cdot 9=27$ (it is clear from the condition that the number of students is no less than 9). However, on the other hand, this number is equal to $9+7+5+3+1=25$. Contradiction.

## Answer

None.