Answer:
a) 270 km
b) 90 km/h
Step-by-step explanation:
If a car left left town Q 15 minutes later than bus left town P, then the car left town Q at 7:45 p.m. Since the car reached town P at 10:45 a.m., then the car was [tex]t_{car}=\{10:45-7:45\}=3[/tex] hours on the road.
If a bus left town P at 7:30 and reached town Q at 12:00, then the bus was [tex]t_{bus}=\{12:00-7:30\}=4\frac{1}{2}[/tex] hours on the road. Since the speed of the bus is 60 km/h, then the distance between towns P and Q is
[tex]D=60\cdot 4.5=270\ km.[/tex]
Now the speed of the car is
[tex]v_{car}=\dfrac{D}{t_{car}}=\dfrac{270}{3}=90\ km/h.[/tex]
