If there is $20,000 divided 4 people in the shares you have listed, each of their amounts are below:
$20,000 x .5 = $10,000
$20,000 x .4 = $8,000
$20,000 x .3 = $6,000
$20,000 x .1 = $2,000
The problem with this question is that your shares equal 130%, but you only have 100% to distribute.