Chapter 4.8, Problem 9P

To determine

To determine the Bus’s city travelled speed.

Answer to Problem 9P

The bus city travelled speed is 43 km/h.

Explanation of Solution

Given information,

Total Distanced travelled: 387 km

Time taken: 5 hours

In the city traffic:

time taken = 1 hour

speed = x km/h

distance = speed × time taken = x km

In the highway:

time = 4 hours

speed = 2x km/h

distance = speed × time = $4\times 2x=8xkm$

As we know that,

total distance travelled = city total travelled + highway total travelled = 387 km

therefore, putting the value in the above equation we get-

  $\begin{array}{l}\begin{array}{l}x+8x=387km\hfill \\ 9x=387\hfill \end{array}\\ x=\frac{387}{9}\\ x=43\end{array}$

So, the bus city travelled speed = 43 km/h.

and the bus highway speed was = $2\times 43=86km/h$ .