M four students in a school with 100 students, 15 play football, 20 play volleyball played both volleyball and football, of 10 people, find the number of students who do not play both .
Graders, m (4) In one of the schools have 100 people play football for 20 people to play volleyball, 15 people in this play of volleyball and soccer, 10 people who find the number of students who do not play sports both types .
Students in the schools, 4 of 20 100 people playing soccer, volleyball, 15 of them in this number and play volleyball and soccer, and 10 number of students who do not play sports for both types of