Astone is an english measure of weight. there are 14 lb in 1 stone and 2.2 lb in 1 kg. a certain person weighs 9 stone. if you wanted to convert the person’s weight to kilograms, what conversion factor should you use?

and you.

Here, 14 lb = 1 stone
1 lb = 1/14 stone

2.2 lb = 1 Kg
1 lb = 1/2.2 Kg

Compare both equations, 

1/14 stones = 1/2.2 Kg
1 stone = 14/2.2 Kg
1 stone = 6.36 Kg  [ It's Our Factor ]

Now, person weighs 9 stone would be: 6.36 * 9 = 57.27 Kg

Hope this helps!

What's the denominator