[奧林匹克挑戰題]1

Let d be the HCF of a and c
then a=dm, c=dn
we have
b=ca/(a+c)=dmn/(m+n)
and d(m-n)=101
So d=101 and m-n=1
Because (m+n)|d
So m+n=101
That is m=51 , n=50
b=(101)(51)(50)/(101)=2550

呢個answer唔係positive integer.......
c x c-101c
_________ = b
99