There are 72 students that signed up for canoeing, and 23 students that signed up for trekking. 13 of these 23 students also signed up for canoeing.
Use the following equation to find the amount of people that signed up for an activity:
![72 + 23 - 13 = 82](https://img.qammunity.org/2019/formulas/mathematics/high-school/v7wkabxmzt16es0us1vp8gzvor8bxxlubi.png)
82 students signed up for canoeing or trekking.
Subtract this total from the total amount of students to find the total that did not sign up for an activity:
![180 - 82 = 98](https://img.qammunity.org/2019/formulas/mathematics/high-school/5h2m27w1ujgmy69modaugq7uzi0ga216hm.png)
Divide this number by the total amount of students in the camp:
![98 / 180 = 0.54](https://img.qammunity.org/2019/formulas/mathematics/high-school/kpuhs84wbzf5vdbhl8cblfee2hflptuh29.png)
Multiply this decimal by 100 to convert into a percentage:
54% of students did not sign up for neither canoeing nor trekking.