Lets say, for ease, that the vat can hold a total of 70 gallons (or whatever you would like to use.) Use whatever number you want, I just picked this because it gives us a lot of clean numbers. 
Now, if the inlet can fill it in 7 hours, that means that it is adding 10 gallons per hour. (70 gal/7 hours = 10 gal/hr)
For the outlet, use the same process, and you find that it drains the vat at 7 gallons per hour. 
So, if you subtract the outlet from the inlet, you get 10 - 7 = 3 gallons per hour added. 
Now just divide the size of the vat by that number, and you find your answer. 
70 gallons / 3 gallons per hour = 23 1/3 hours. 
        
             
        
        
        
Answer:
counted down
Step-by-step explanation:
it was counting up and went down by couting down in 2
 
        
             
        
        
        
Answer:
Yes
Step-by-step explanation:
Just trust
 
        
                    
             
        
        
        
D. works because if you work it out that means 2n=140 and then divide by 2 which means n=70 and the other number is 71
        
             
        
        
        
Answer:
Celia can get 4 goldfish for $1.00.
Step-by-step explanation:
If you take 12 and divide it by 3 you get 4. I hope this helps.