Question

Question 60

In questions which of the following vary directly and which vary inversely with each other and which are neither of the two?
(i) The time taken by a train to cover a fixed distance and the speed of the train.
(ii) The disatnce travelled by CNG bus and the amount of CNG used.
(iii) The number of people working and the time to complete a given work.
(iv) Income tax and the income.
(v) Distance travelled by an auto-rickshaw and time taken.

Answer 1

(i) The time taken by a train to cover a fixed distance and the speed of the train are inversely proportional.
e.g. Let a train cover 100 km in 30 min with speed 200 km/h.
Then, the same train cover 100 km in 30 min with speed 200 km/h.
(ii) The distance travelled by CNG bus and the amount of CNG used are directly proportional.
e.g. Let a CNG bus can travelled 10 km in 1 kg of CNG.
Then, the same CNG bus travelled 20 km in $2\times 1$= 2 kg of CNG.
(iii) The number of people working and the time to complete a given work are inversely proportional to each other.
e.g. Let 20 workers can complete a work in 1day.
Then, 10 workers can complete the same work in 2 days.
(iv) Income tax and the income are directly proportional to each other. e.g. Let Mr X have 4.5 lakh annual income.
Then, he pay 10% income tax on his income.
But if Mr X have 5.5 lakh annual income, theri,S has to pay 30% income tax on his salary/income.
(v) Distance travelled by an auto rickshaw and time taken are directly proportional to each other.
e.g. Let an auto rickshaw takes 2 h to travel 10 km.
Then, it will take 4 h to travel 20 km.