€1575 shared as ratio: 1:2:1/2 = 1:2:0.5
Now place an 'x' after each ratio term to signify the amount they have in common. Then set total sum of ratios equal to the total.
1x + 2x + 0.5x = 1575
3.5x = 1575
3.5x/3.5 = 1575/3.5
x = €450
But the smallest share was 1/2 or 0.5x, so 1/2 × 450 = €225