Answer:
12.5
Step-by-step explanation:
.25 x 50= 12.5
 
        
             
        
        
        
Total: 73
dogs: x
cats: 2x+10
2x+10+x=73
3x+10=73
3x=63
x=21
dogs: x
dogs: 21
cats: 2x+10
cats: 52
Check answer: 
cats+dogs=73
52+21=73
There's no need for a system of linear equations if you were to solve a real life problem like this. In calculus, they don't give a rat about HOW you get your answer to an easy algebra 1 equation, as long as you used one of the correct methods and got the right answer. 
Best of luck my friend. :)
        
             
        
        
        
Volume formula of a sphere:


r³
given:
r = 3 
V = 


(3)³
V = 

 × 27

V = 36

 units³ (in terms of 

)
V = 113.097 units³ ≈ 113.1 units³
 
        
        
        
Answer:
75:80   OR    15:16
Step-by-step explanation:
 
        
             
        
        
        
One of them is 13 and the other is 28