This is the concept of volume of solid materials. Volume is of a rectangular prism is given by:
volume=length*width*height
length=6 units
width=3 units
height=4 units
thus;
volume=6*3*4=72 cubic units
        
             
        
        
        
Answer:
18
Step-by-step explanation:
When you do subtraction and addition you do it from left to right. So I did 16-3 which is 13, and I did 13+5 which is 18. 
Cheers,
Yeet
 
        
                    
             
        
        
        
Answer:
Option D (r(t) = 3.50t +25
; r(8) = 53)
Step-by-step explanation:
The fixed cost to rent the kayak $25. This is the cost which remains fixed irrespective of the usage of the kayak. The variable cost of using the kayak is the cost which depends on the usage of the kayak. It is mentioned that the kayak is used for 4 hours and the company charges $3.5 for every half hour. The cost function is given by:
r(t) = 25 + 3.5t ; there r is the total cost of using the kayak and t is the number of half-hours the kayak is used. 
4 hours means that there are 8 half-hours. Therefore, t=8. Put t=8 in r(t).
r(8) = 25 + 3.5*(8) = 25 + 28 = 53.
Therefore, Option D is the correct answer!!!
 
        
                    
             
        
        
        
Answer:
Yes, they do
Step-by-step explanation:
Because
6+8=14>9
6+9=15>8
8+9=17>6