class - 8
1. In which of the following cases is there direct
variation between the two given quantities? (Do not
carry out any calculations)
(a) 10 workers finish a job in 6 days. In how many days
will 20 workers finish the same job?
(b) A car runs at a uniform speed. If it covers 135 km in
3 hours, how much distance will it cover in 2 hours?
(c) A tap can completely fill a tank in 11/2 hours. How
much of it can be filled in 34 hours?
(d) Curtain cloth was purchased at Rs. 230 per meter.
How much will 12 meters of cloth cost?
Answers
Answer:
omg its really hard to understand the question..I'm really sry
Answer
(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.