MathLabs

Problem 6

In a sports contest, mm medals were awarded on nn successive days (n>1n>1). On the first day, one medal and 17\frac17 of the remaining m−1m-1 medals were awarded. On the second day, two medals and 17\frac17 of the then remaining medals were awarded, and so on. On the nn-th and last day, the remaining nn medals were awarded. Find mm and nn.
Step 1 of 6: Track the remainder
mr=prizes remaining at the start of day r,m1=mm_r=\text{prizes remaining at the start of day }r,\quad m_1=m
Detailed analysis

Let mrm_r be the number of prizes at the start of day rr, with m1=mm_1=m the total. On the final day, the rule for day nn and the fact that all remaining prizes are awarded give mn=nm_n=n.