Answer
See below
Work Step by Step
The equation for an exponential growth model: $p=a(1+r)^t$
The opening bid for a pair of in-line skates is $\$50$, so $a=50$
The price of the skates increases by $10.5 \%$ per bid, so $r=0.105$
Hence, $p=50(1+0.105)^n=50(1.105)^n$
