A 7-digit number made up of all distinct digits $8, 7, 6, 4, 2, x$ and $y,$is divisible by $3.$ The possible number of ordered pair $(x, y)$ is

The sum of digits is divisible by 3.

i.e., $8+7+6+4+2+x+y$ or $27+x+y$ is divisible by 3

$\therefore x+y$ must be divisible by 3.

Then, possible ordered pairs are

$(0,3),(3,0),(1,5),(5,1),(0,9),(9,0),(3,9),(9,3)$

$\therefore$ Number of ordered pairs $=8.$