This is a word problem signifying an algebraic expression.
Translating this to mathematics:

add 4 to both sides.
divide 16 to both sides.
this is:
Answer:
7
Step-by-step explanation:
number of diagonals in a regular polygon = number of sides - 2.
A nonagon is a polygon having 9 sides.
Total number of diagonals in a regular nonagon
= 9 - 2
= 7
There are 150 students in Hannah's school.
Sum of books donated by the students =b.
Average books donated by each student =
It is given Hannah donated 3 times as many books each student donated.
Number of books donated by Hannah= 
The expression of the number of books donated by Hannah= 
The answers are the following
1. B
2. A
3. B
4. A
Answer:
a)12 b)12 c)36
Step-by-step explanation:
a)find the least common multiple. the number of marbles is that number * n (where n is an integer)
b) the least common multiple. it is 4*3=...
c)12*3 =?
then just divide by 2,3,4 to get the answer