Răspuns :
20
5,15,25,35,45,52,52,53,54,55,56,57,58,59,65 ,75,85,95. + un cinci de la 55
15,25,35,45,50,51,52,53,54,55,56,57,58,59,65,75,85,95=18 de 5+ 1 de la 55= 19 de 5