Well, I would just reverse it. It seems you just have to reverse the whole problem.
Answer:
Lori will have 
cavity if she brushed for 
each night.
Step-by-step explanation:
As the question suggests cavities developed varies inversely with the number of seconds spent on brushing.
Lets take the terms as 
,where 
is the constant of proportionality.
And
c = Number of cavities developed each year
t = Number of minutes spent on brushing per night
Now we will plugging the values of the given terms and find the value of ,for this we can re-arrange it as...
and 
Now as Lori will increase her brushing time so as the cavity will decrease.
So for this we have been given,
and 
.
As 
So as per Paul's observation if Lori brushed for 
at night she will have cavity on that year.
Answer:
here is your answer........
The answer to your question would be B because you divide 10 by 3.5 to get 3, then you would divide 12 by 3 to get 4. Multiply them together to get 14
You can use Soh Cah Toa to get your answer, in other words, sin cos tan. If you already have x, that means you probably used tan, which is adjacent and opposite. Now for y, you are trying to find the hypotenuse so you could use, sin or cos, for sin you would use the adjacent (x) and the hypotenuse (y) and for cos, you would use opposite (4) and the hypotenuse (y). This is all based on the angle 45.
