The simplest proportion of 2 dozen:3 score is

2 dozens : 3 scores
(2*12) : (3*20)
24 : 60
2 : 5

1 dozen = 12 unit2 dozen = 24 unit
3 score =20 unit
3 x20 unit = 60 unit
so the answer is[tex] \frac{24}{60} \\ \frac{24:12}{60:12} \\ \frac{2}{5} [/tex]