Answer:
17
Step-by-step explanation:
There are a total of 39 students.
students.
The number of students that play football is twice as much as the number of students that play volleyball.
Let the number that plays volleyball be x then the number that plays football will be 2x. This we have
x + 2x = 39
3x = 39
x = 13
The total number that plays volleyball is 13.
The total number that plays football will be 2 x 13 = 26
Since 9 students play both sports, the number of students that plays only football will be 26 - 9 = 17.
