Answer:
9
Step-by-step explanation:
Let's say Mark is M and his brother is B.
M+5=B
M+B=23
Now we can solve using subsitution.
M+M+5=23
(Subtract 5 from both sides)
2M=18
M=9
Hope this helped!
<span>seventy-seven hundredths.</span>
Answer:

Step-by-step explanation:
A rectangular prism is a polyhedron with six rectangular faces. The volume of a prism is given by:
Volume = width * height * length
From the diagram, the rectangular prism is made up of cubes. Each cube is has a size of 1/3 ft by 1/3 ft.
The height of the prism is made up of 5 cubes. Height = 5 * 1/3 = 5/3 ft.
The length of the prism is made up of 3 cubes. length = 3 * 1/3 = 1 ft.
The width of the prism is made up of 2 cubes. Width = 2 * 1/3 = 2/3 ft.
The volume of the prism = width * height * length = 2/3 * 5/3 * 1 = 10/9 ft³ = 
28.23 is the volume of something if the diameter is 2 cm and the height is 9 cm.
If 1/4 of x is 16, we multiply 16 x 4 which will give us x=64. 3/4 of 64 = 48