We know that
The formula for combinations is
C=n!/[(n-r)!*r!]
where
n is the total number of objects you choose from
r is the number that you choose to arrange
in this problem
n=15 students
r=4 students
C=15!/[(15-4)!*4!]-----> C=15!/[11!*4!]---> (15*14*13*12*11!)/(11!*4*3*2*1)
C=(15*14*13*12)/(24)----->C=1365
the answer is
1365
Answer:13.86km
Step-by-step explanation: see attachment
Answer:
The Sum of the areas of theses triangles is 169/3.
Step-by-step explanation:
Consider the provided information.
The hypotenuse of an isosceles right triangle is 13 inches.
Therefore,

Then the area of isosceles right triangle will be: 
Therefore the area is: 
It is given that sum of the area of these triangles if this process is continued infinitely.
We can find the sum of the area using infinite geometric series formula.

Substitute
in above formula.



Hence, the Sum of the areas of theses triangles is 169/3.
Answer:
1/4 - 1/3i
Step-by-step explanation:
(4+3i)(-i) / 12i(-i)
= 3 - 4i / 12