The coach has to select 2 co- captains from the 15 girls out for

soccer. How many selections are

possible?

105 selection s

Step-by-step explanation:

Given:

The coach has to select 2 co-captains from the 15 girls out for soccer

n = 15

r = 2

The number of selections possible is;

N = nCr = n!/r!(n-r)!

Since no other is specified.

Substituting the values of n and r;

N = 15C2 = 15!/2!(15-2)!

N = (15×14)/2

N = 105

Therefore, she have 105 possible selections

he used the algebra tiles correctly.

step-by-step explanation:

given : 3x(2x-1)

solution :

since he used algebra tiles .

armando's solution is the same in the solution shown in figure

as he distributed 2x into x and x and wrote them vertically

and also write   -1 vertically

and 3x into x and x and x and wrote it horizontally

performing the multiplication in the algebra tiles we get

and solving the given expression :

3x(2x-1)

since solving the expression using tiles   and solving the expression algebraically we get the same answer

thus   we can choose the first statement as the answer to this problem which is "he used the algebra tiles correctly".