Answer
7
Work Step by Step
For t = 1 the instantaneous velocity is $\lim\limits_{b \to 1} \frac{s(b) - s(1)}{b-1}$
$s(b)=b^{2} + 5b + 2$
$s(6) = 8$
The instantaneous rate of change is then: $\lim\limits_{b \to 1} \frac{b^{2} + 5b + 2-8}{b-1}= \lim\limits_{b \to 6} \frac{(b-1)(b+6)}{b-1}=\lim\limits_{b \to 1}(b+6) = 7$