Answer:
10 
Step-by-step explanation:
Hi there, hope you are having a nice day!
All we should do is plug in the value of b:
12-2
10 (Answer)
Hope you find it helpful.
Feel free to ask if you have any questions.

135 sea shells more
65-200 equals to 135
Answer:
Gimme some time
Step-by-step explanation:
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