Question

The formula which relates distance, d , speed, s and time, t is = × . (a) Rearrange this formula so that s is the subject. ______________________________________________________________________

(b) Calculate the average speed s that a truck travels for a journey of 748 km which takes 11.5 hours. ______________________________________________________________________ ______________________________________________________________________

Answer 1

1. After rearranging the formula as 's' i.e speed is the subject will be given as

`speed = (distance)/(time) \\ss = (dd)/(tt)`.

2. The average speed of a truck that travels a journey of 748 km in 11.5 hours is 65.04 kilometre per hour.

Explanation:

Ans 1. subject means it come first in the sentence, hence here question is like write speed first in the formula so we have

`speed = (distance)/(time) \\ss = (dd)/(tt)`

Ans 2.

Given :

Total distance of a journey = 748 km

Total time taken for the journey = 11.5 h

To Find:

Average speed =?

Solution :

average speed is defined as of total distance covered divided by total time taken.

So, we have

`\textrm{average speed} = \frac{\textrm{total distance covered}}{\textrm{total time taken to complete total distance}} \\= (748)/(11.5) \\= 65.04\ km/h`