6m............1 (lucrarea)...........48h
6m..............x................................16 sunt dp
x=16*1/48=1/3
1-1/3= 3-1/3= 2/3
6m............1l...................48h
8m...........2/3...................y
48/y= 8/6 * 1/ 2/3
48/y=8/6 *3/2
48/y=2
y=48/2
y=24
16+24=40h