Sub x = 2-y^2 to Q, we get:
Q = 3(2-y^2)*y^2
let y^2 = k
Q = 3(2-k)k = 3(2k-k^2)
2k-k^2 has a max when k = 1
Then y^2 = 1 -> y = 1 or -1
        
             
        
        
        
we know that
1) Lily swims a  -meter race
-meter race
2) She swims the first half in  seconds
 seconds
3) She swims the second half in  seconds
 seconds
so
To find the total time to swim the whole race sum the time in the first half plus the time in second half

therefore
<u>the answer is</u>

 
        
                    
             
        
        
        
Answer:
22.5 hours
Step-by-step explanation:
191.25 divided by 8.50 hours will get you the total amount of hours she worked