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 4 of 6: Evaluate the geometric sum
m=36+(n−6)7n6n−1m=36+\frac{(n-6)7^n}{6^{n-1}}
Detailed analysis

The standard finite arithmetic-geometric sum simplifies the formula to m=36+(n−6)7n6n−1m=36+\frac{(n-6)7^n}{6^{n-1}}.