Question

Which of the following varies inversely with each other
A. speed and distance covered
B. distance covered and taxi fare
C. distance travelled and time taken
D. speed and time taken

Answer 1

Hint: This question can be approached in a trial-and-error method. That is, we can approach the options one by one and see which one of the options are inversely proportional to one another. Inversely proportional means that, if one quantity increases, the other should decrease or vice versa. This will lead us to the required solution.

Complete answer:
Let us start analyzing the options one by one:
(A) Speed and distance covered: We know that speed is defined as the distance travelled per unit time. This means that the change in distance affects the change in speed proportionally and not inversely.

(B) Distance and taxi fare: Logically, we cannot say that, as the distance increases, the taxi fare decreases. This means that this option is also wrong

(C) Distance travelled and time taken: Distance and time are directly proportional because when we cover more Distance, we consume more time. This option is wrong as well

(D) Speed and time taken: Speed is defined as the rate of change of distance. Logically, when the time taken for a body to reach a certain place is more, it is said to have less speed. This means that when speed increases, time decreases and hence they are inversely proportional.

Therefore, option (D) is correct.

Note: Speed is defined as the ratio of the distance travelled by a body to the time taken by the body to cover the particular distance. It is a scalar quantity, which means that it has only magnitude and no direction. Speed is often confused with velocity but the main difference between the two is that speed is scalar and velocity is a vector quantity.