Check whether x and y vary inversely or not

x	y
10	90
30	30
60	20
10	90

$∵ x$1y1 = 10 \times 90 = 900,\\[1em] x2y2 = 30 \times 30 = 900,\\[1em] x3y3 = 60 \times 20 = 1,200,\\[1em] x4y4 = 10 \times 90 = 900,\\[1em]

So, $x$1y1 = x2y2 ≠ x3y3 ≠ x4y4

Hence, x and y do not vary inversely.