B. V=9
Multiply it out, then subtract 99 from both sides, then divide by 11
Answer:

Step-by-step explanation:
Let the numbers be 
Such that:

Make z the subject

For their product to be maximum, we have:

Substitute
in 

Open bracket

Differentiate w.r.t x and y


Since the products are maximum, then 
For 

Factorize:

Split

Make y the subject

For 

---------------------------------------------------
Substitute y = 0


Factorize



---------------------------------------------------
Substitute 



Re-arrange


Factor x out

Divide through by x



Recall that: 


Take LCM


Recall that:


Take LCM


Hence, the numbers are:

The answer would be "both groups show about the same average time"
The graph is at a slope:1 with a y-intercept:-4