First of all, we need to make a draw of the problem to understand better:
Both vehicles have a point of interception when pass t=14.7 minutes
The distance between two cities are 81.4 km, then:

At time of interception t, Police car travels a distance:

Similary, Fire truck travels a distance of:

But the fire truck is comming from the opposite direction.
When they meet at time t we have the next equation:

Now we convert time from minutes to hours:

After that, we make a relation between two speeds, knowing that:
![v_{police\text{ car}}=v_{fire\text{ truck}}+6.5\text{ }\frac{\operatorname{km}}{h}]()
Then:
![\begin{gathered} v_{police\text{ car}}\cdot t=d-v_{fire\text{ truck}}\cdot t \\ (v_{fire\text{ truck}}+6.5\text{ }\frac{\operatorname{km}}{h})\text{.t}=d-v_{fire\text{ truck}}\cdot t;\text{ we solve to spe}ed\text{ of fire truck} \\ v_{fire\text{ truck}}\cdot t+6.5\frac{\operatorname{km}}{h}\cdot t=d-v_{fire\text{ truck}}\cdot t \\ v_{fire\text{ truck}}\cdot t+v_{fire\text{ truck}}\cdot t+6.5\frac{\operatorname{km}}{h}\cdot t=d;\text{ we replace t=0.245 h and d=81.4 km} \\ 2\cdot(0.245)\cdot v_{fire\text{ truck}}=\text{ 81.4 km -6.5}\frac{\operatorname{km}}{h}\cdot(0.245h) \\ 0.49\cdot v_{fire\text{ truck}}=81.4-1.5925 \\ v_{fire\text{ truck}}=(79.8075)/(0.49)=162.87\frac{\operatorname{km}}{h} \end{gathered}]()
Finally, we find the speed of car police
![\begin{gathered} v_{police\text{ car}}=v_{fire\text{ truck}}+6.5\text{ }\frac{\operatorname{km}}{h} \\ v_{police\text{ car}}=162.87\frac{\operatorname{km}}{h}+6.5\text{ }\frac{\operatorname{km}}{h} \\ v_{police\text{ car}}=169.4\text{ }\frac{\operatorname{km}}{h} \end{gathered}]()