Răspuns :
d=93
c=15:3=5
r=6:2=3
93:a=5 rest 3
93=5a+3
93-3=5a
90=5a
a=90:5=18
93:18=5 rest 3
c=15:3=5
r=6:2=3
93:a=5 rest 3
93=5a+3
93-3=5a
90=5a
a=90:5=18
93:18=5 rest 3