Answer
31 s
Work Step by Step
Let's take,
Your velocity relative to the ground = $V_{YG}$
Your velocity relative to the speed ramp = $V_{YR}$
Speed ramp's velocity relative to the ground = $V_{RG}$
Since you walk with respect to the ramp at the same rate that you walk on the ground, we can write,
$V_{YR}=\frac{105\space m}{75\space s}=1.4\space s $
We know that,
$V_{YG}=V_{YR}+V_{RG}$ ; Let's plug known values into this equation.
$V_{YG}=1.4\space m/s+2\space m/s=3.4\space m/s$
Desired time = $\frac{d}{yV_{YG}}=\frac{105\space m}{3.4\space m/s}=31\space s$
