Running At A Average Of 40 Km/Hr ,A Bus Competes A Journey In 4 $\frac{1}{2}$ Hours . How Much Time Will The Return Journey Take If The Speed Is Increased To 45 Km/Hr.

Given: 

Running at an average Of 40 Km/Hr ,a bus competes a journey In 4 $\frac{1}{2}$

To do: Find how much time will the return journey will take if speed is increased to 45km/hr.

Solution:

Speed = 40 km/h

Time = 4.5 hours 

Distance = Speed $\times$ Time = 40 $\times$ 4.5

Distance = 180 km

New speed = 45 km/h

Distance = 180 km

Time taken = $\frac{Distance}{ Speed}$ =$ \frac{180}{ 45}$

Time taken = 4 hours

Therefore, the return trip will be 4hours long