Răspuns:
a+b+c=3186
a:b=6 r15 rezultă a=6b+15
b:c=5 r21 rezultă b=5c+21
a=6b+15
b=5c+21 deci a=6(5c+21)+15 , a=30c+126+15 ,a=30c+141
a+b+c=30c+141+5c+21+c=36c+162
36c+162=3186
36c=3186-162
36c=3024
c=3024:36
c=84
b=5c+21=5×84+21=420+21
b=441
a=6b+15=6×441+15=2646+15
a=2661
a=2661
b=441
c=84
