a) 4kg = 400dag

$\frac{400}{80}=\frac{5}{1}=5:1$

b) 1h= 60min

$\frac{60}{20}=\frac{3}{1}=3:1$

 

c) 0,3m = 30cm

$\frac{50}{30}=\frac{5}{3}=5:3$