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:
135000/6000=X
22.5=X
So this building would need 23 fire extinguishers <span />
Answer:
x = 2u -v
Step-by-step explanation:
X is the excess when we try to squeeze 2 u's on the side v,therefore
x = 2u -v
Answer:
C.
Step-by-step explanation:
Square Perimeter = 4(4x-1)
Rectangle Perimeter = 2(2x+1) + 2(x+2)
Square Perimeter = Rectangle Perimeter
4(4x-1) = 2(2x+1) + 2(x+2)
16x - 4 = 4x + 2 + 2x + 4
16x - 4 = 6x + 6
-6x +4 -6x +4
10x = 10
x = 1
