Answer:
the expression is: 
and 2730 different ways are possible.
Step-by-step explanation:
In the given question we have to choose a president, vice
president, and secretary.
Permutations are used when order is important so, as in the given question order is required. We would use permutations
The formula used is:
where:
n=total number of objects
r=number of objects selected
In our case: n=15, r=3
Putting values and finding the answer:

So, the expression is: 
and 2730 different ways are possible.
Answer:
7
Step-by-step explanation:
7x4=28
6x4=24
So it cant be 6 or anything less
It would be (4, 5) because add the 2nd and third than you get (4, 5)
Answer: x=316 and y=41
Step-by-step explanation:
1. x+y=357
2. x-y=41
3. x+y=357
<u>x-y=41</u>
x=316 y= 41
Answer:
dont know srry
Step-by-step explanation: