Think of it this way:
_ _ _ (3 digit number)
for the first blank you could have 7 possibilities
for the second blank you could have 6 possibilities 
for the third blank you could have 5 possibilities 
because each time you fill in a blank one number is removed from the list of possibilities 
7×6×5=210. there are 210 possibilities 
        
             
        
        
        
Answer:
The volume of the solution with 20% acid is 27 gallons and the one with 10% acid is 18 gallons
Step-by-step explanation:
Myra needs to mix "x" gallons of the solution with 20% and "y" gallons of the solution with 10%. The volume of the final solution must be 45 gallons, therefore:
x + y = 45
The concentration of acid of the final solution is:
0.2*x + 0.1*y = 45*0.16
0.2*x + 0.1*y = 7.2
Therefore we have a system of equation:
 x + y = 45
0.2*x + 0.1*y = 7.2
We need to multiply the first equation by -0.1:
-0.1*x -0.1*y = -4.5
0.2*x + 0.1*y = 7.2
We now sum both equation:
0.1*x = 2.7
x = 2.7/0.1 = 27 gallons
y = 45 - 27  = 18 gallons
 
        
             
        
        
        
Answer:
Volume= 10 cm³
Step-by-step explanation:




 
        
                    
             
        
        
        
Hello,
Let's assume k the ratio.

 
 
        
        
        
Cubed root (x^2) I can’t add the radical here but it would be the 3radical(x^2)