Answer
$\approx 5.1$ feet per second
Work Step by Step
distance = (rate)$\times$(time) $\Rightarrow$ time = $\displaystyle \frac{\text{distance}}{\text{rate}}$
Let x be the walking speed (rate).
We are given:
$\displaystyle \frac{105}{x+1.8}=\frac{50}{x-1.8} \qquad$ ... $/\times(x+1.8)(x-1.8)$
$105(x-1.8)=50(x+1.8)$
$ 105x-189=50x+90\qquad$ ... add $189- 50x$
$ 55x=279\qquad$ ...$ /\div 55$
$x\approx 5.072727 \approx 5.1$ feet per second
walking speed $\approx 5.1$ feet per second
