Observe the following tables and find which pair of variables (here x and y) are in inverse proportion.
i)
x | 50 | 40 | 30 | 20 |
y | 5 | 6 | 7 | 8 |
Finding if x and y are in inverse proportion:
Two quantities x and y are said to vary in inverse proportion, if there exists a relation of the type xy = k between them, k being a constant
so, calculating xy for each case,
we have
,
Clearly, xy is not equal to a constant value 'k',
Hence, x and y are not inversely proportional.