Question

State whether the following are a case of Direct or Inverse proportion :
(a) The speed of a car and the distance travelled.
(b) The time taken for a journey and the distance travelled at uniform speed.
(c) The time taken for a fixed journey and the speed of the vehicle.

Answer 1

Hi,

$$\begin{gathered} \mathrm{We}\mathrm{know}\mathrm{that} \\ \mathrm{speed}=\frac{\mathrm{distance}}{\mathrm{time}} \\ \mathrm{So}\mathrm{here}\mathrm{speed}\mathrm{\alpha }\mathrm{distance}\left[\mathrm{If}\mathrm{time}\mathrm{constant}\right] \\ \mathrm{and}\mathrm{speed}\mathrm{\alpha }\frac{1}{\mathrm{time}} \\ \mathrm{So}\mathrm{a})\mathrm{direct}\mathrm{proportion} \\ \mathrm{For}\mathrm{b}) \\ \mathrm{distance}=\mathrm{speed}\times \mathrm{time} \\ \mathrm{distance}\mathrm{\alpha }\mathrm{time}\left[\mathrm{Since}\mathrm{speed}\mathrm{uniform}\right] \\ \mathrm{So}\mathrm{it}\mathrm{is}\mathrm{again}\mathrm{direct}\mathrm{proportion}. \\ \mathrm{c}) \\ \mathrm{since}\mathrm{journey}\mathrm{if}\mathrm{fixed}\mathrm{so} \\ \mathrm{D}=\mathrm{constant} \\ \mathrm{Then}\mathrm{speed}\mathrm{\alpha }\frac{1}{\mathrm{time}} \\ \mathrm{It}\mathrm{is}\mathrm{inverse}\mathrm{proportion}. \end{gathered}$$
Regards