Question

1. Which of the following are in direct variation? i. Money deposited in the bank and interest earned on it. ii. Number of workers and the time taken to complete a work. iii. Area of land and its cost. iv. Distance travelled by a taxi and the fare charged​

Answer 1

Explanation:

If y = 27 when x = 6, write the direct variation equation. If y = -7 when x = -14, write the direct variation equation and find y when x = 20. If x = 8 when y = 4, write the direct variation equation and find y when x = 5. y = 1/6x; If x = 36 when y = 6, find x when y = 42. If y = -16 when x = 4, find x when y = 20.

Answer 2

Explanation:

(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.