I have added a screenshot with the complete question.
Answer:
At least 7 more students need to sign up for the field trip to be scheduled
Explanation:
Assume that the least number of students remaining to register for the trip to be scheduled is x.
total number of students = students who already registered + x
We are given that, the least number of students required for this trip is 30. This means that:
total number of students ≥ 30
Now, we know that 23 students already registered.
The inequality now is:
x + 23 ≥ 30
x ≥ 30 - 23
x ≥ 7
This means that at least 7 more students must register for the trip to be scheduled.
Hope this helps :)