Hi
there are 540 workers
Let x and (540 - x) represent the number of techs and packers respectively
Question States
$24x + $20(540-x) = $12,000
solving for x
4x = $12,000 - $20*540
4x = 1200
x = 300, the number of techs. 240 packers. (540-300)
CHECKING our Answer
$24*300 + $20 *240 = $12,000