Question

Which of the following are in inverse proportion ?
(i) The number of workers on a job and the time to complete the job.
(ii) The time taken for a journey and the distance travelled in a uniform speed.
(iii) Area of cultivated land and the crop harvested.
(iv) The time taken for a fixed journey and the speed of the vehicle.
(v) The population of a country and the area of land per person.

Answer 1

(i) We know that more is the number of workers to do a job, less is the time taken to finish the job.
So, it is a case of inverse proportion.

(ii) Considering uniform speed, as the distance to be travelled increases, the time taken to cover it will also increase.

So, this is a case of direct variation.
(iii) Clearly, more is the area of cultivated land, more is the crop harvested.
So, it is a case of direct proportion.

(iv) We know that the more will be the speed of the vehicle, the distance will be covered in lesser time.
So, it is a case of inverse proportion.
(v) Clearly, more is the population, less is the area of land per person in a country.
So, it is a case of inverse proportion.