Answer: 18.29%
Explanation:
There are 350 students. Out of these students, 70 signed up for the Army, 64 for the Airforce, 56 for the Navy and 160 for the Marines for a total of 350.
The percentage of students who signed up for the Airforce out of the total can be calculated by:
= number of students (airforce) / total number of students * 100
= 64/350 * 100
= 18.29%