The variation of speed $(\mathrm{in} \mathrm{m}/\mathrm{s})$ of an object with time (in seconds) is given by the expression $V\left(t\right)=V_0-5t+5t^2$

The following plot gives the variation of acceleration $\left(\mathrm{m}/{\mathrm{s}}^2\right)$ with time $\left(s\right)$ for an object that started from rest at time $t=0 \mathrm{s}.$ The velocity at time $t=15 \mathrm{s}\left(v_{15}\right)$ and at $25 \mathrm{s}$ $\left(V_{25}\right)$, respectively are