Kinematics of motion in a straight line — practice question

A cyclist moves along a straight horizontal road at a speed of $4\,\text{m s}^{-1}$ as she passes point $O$. She then accelerates uniformly over a distance of $42\,\text{m}$ until her speed becomes $V\,\text{m s}^{-1}$. After that, she continues at $V\,\text{m s}^{-1}$ for $50\,\text{m}$ and then slows down at $2\,\text{m s}^{-2}$ before stopping completely. The distance covered during deceleration is $16\,\text{m}$.