The answer is 3a + 2b + 8
Answer:
Part 1) 
Part 2) 
Part 3) 
Part 4) 
Part 5) 
Part 6) 
Step-by-step explanation:
Part 1) we know that
The shaded region is equal to the area of the complete rectangle minus the area of the interior rectangle
The area of rectangle is equal to

where
b is the base of rectangle
h is the height of rectangle
so



Part 2) we know that
The shaded region is equal to the area of the complete rectangle minus the area of the interior square
The area of square is equal to

where
b is the length side of the square
so



Part 3) we know that
The area of the shaded region is equal to the area of four rectangles plus the area of one square
so



Part 4) we know that
The shaded region is equal to the area of the complete square minus the area of the interior square
so



Part 5) we know that
The area of the shaded region is equal to the area of triangle minus the area of rectangle
The area of triangle is equal to

where
b is the base of triangle
h is the height of triangle
so



Part 6) we know that
The area of the shaded region is equal to the area of the circle minus the area of rectangle
The area of the circle is equal to

where
r is the radius of the circle
so


Answer:
A1) 125
A2) 47.5%
B) 30
Step-by-step explanation:
Remember 'of' in this sentence means times(*). % shows a certain number/100.
a1) 48% 'of' what number is 60?
(let unknown number be x)
48/100 *x=60
Solve the equation, and the answer is x=125
a2) what percentage 'of' 120 is 57?
(let the unknown percentage be x)
(x/100)*120=57
x=47.5%
b) 24 students= 80% of the total number of students
1%=24/80
100% of the total number of students=30
So, there are total of 30 students
Answer:
2
Step-by-step explanation:
Use order of operations PEMDAS
3^2 = 9 * 2 = 18
20-18= 2