480700. The different combinations of students that could go on the trip with a total of 25 student, but only 18 may go, is 480700.
The key to solve this problem is using the combination formula
. This mean the number of ways to choose a sample of r elements from a set of n distinct objects where order does not matter and replacements are not allowed.
The total of students is n and the only that 18 students may go is r:

The formula for this is A= a + b/2 x h.
Answer:
9652
Step-by-step explanation:
Hope that helps!
Answer:
225 m2
Step-by-step explanation:
area= side*side
= 15x15
225 m2
I'm not 100% sure, but I'm pretty sure it's 1/12, 1/12, 1/12, 1/12