here our distance is given with respect to ticket booth
initial distance is given 50 m from the booth
So our initial position is
![x_i = 50 m](https://img.qammunity.org/2019/formulas/physics/high-school/pddwrch3gygtn5uz59u3ydioztbrzbe1wx.png)
now after this finally we reach at final position
![x_f = 5 m](https://img.qammunity.org/2019/formulas/physics/high-school/933nh54d01jmi6uwnr6dq2sdioj45lgaxf.png)
now change in position is given as
![\Delta x = x_f - x_i](https://img.qammunity.org/2019/formulas/physics/high-school/6po941qcqzd0sg6licypwfaqb7onxgizqs.png)
![\Delta x = 5 - 50 = - 45 m](https://img.qammunity.org/2019/formulas/physics/high-school/mgh7dugq2wsdplaycmcj8u293jvv2f6fja.png)
so change in position is 45 m in magnitude and since we are coming closer to the booth so its coming negative in sign