A would be 6/12 (1/2) and B would be 1/12. To make this easier to understand, think of it this way. 6+1=7, and 6-1=5. In the future, find what adds to 7 and begin plugging in numbers until you get the correct answer.
When x varies inversely with y then you'll have
xα1/y
x=k/y where k is the proportionality constant
when x=8. y=10. k=?
8=k/10
make k the subject of the formula
k=10×8
k=80.
When x=6. y=?.k=80
6=80/y
Make y the subject of the formula
y=80/6
y=40/3
The answer is 3. have a good day
The answer to this is 660