found the answer approxim$$tally but it i slightly different than manual manual took different velocities for vehicles after collusion is my aolution valid

You have been hired as an expert witness in a court case involving an automobile accident. The accident involved car A of mass $1500$ kg which crashed into stationary car B of mass $1100$ kg $.$ The driver of car A applied his brakes $15$ m before he skidded and crashed into car B$.$ After the collision, car A slid $18$ m while car B slid $30$ m $.$ The coefficient of kinetic friction between the locked wheels and the road was measured to be $0\mathrm{.}60.$ Show that the driver of car A was exceeding the $55-m\frac{i}{h}(90k\frac{m}{h})$ speed limit before applying the brakes.

$K_{MC}={}_{FR}=1500(9\mathrm{.}8)(0\mathrm{.}6)(18)+1100(30)(0\mathrm{.}6)(9\mathrm{.}8)=352800J$

$K_{AC}=\frac{1}{2}2600(\frac{15}{26}Q{)}^2,Q28\mathrm{.}55$

$W_{FQBC}=1500.(9\mathrm{.}8)(0\mathrm{.}6)(15)=132\mathrm{.}300J$

$F_{\text{I}\text{E}\text{C}\text{i}\text{o}\text{n}\text{B}\text{e}\text{f}\text{o}\text{r}\text{e}\text{c}\text{o}\text{l}\text{.}\text{s}\text{i}\text{o}\text{n}(A)}$

$E_A=\frac{1}{2}1500(28\mathrm{.}55{)}^2+132\mathrm{.}300=\frac{1}{2}1500(Q_i{)}^2$

$Q_i=31\mathrm{.}49$mIs$=70\mathrm{.}45m\frac{i}{h}$