Question

The distance between Mumbai and Delhi is usually expressed in units of:
A. Decameter
B. Meter
C. Centimeter
D. Kilometer

Answer 1

Compare every option with kilometers. Check which unit of distance measurement between Mumbai and Delhi is more suitable. The largest unit among the given options can be the suitable unit for such a large distance measurement.

Complete step by step solution:
We know that the distance between Mumbai and Delhi is around 1400 km.To answer this question, let’s explain every option one by one. We know that decameter is the unit of distance measurement. It represents 1 decameter equals 10 meters. We can express the distance between Mumbai and Delhi in decameter as follows,
$\left( {1400\,km} \right)\left( {\dfrac{{1000\,m}}{{1\,km}}} \right)\left( {\dfrac{{1\,dam}}{{10\,m}}} \right) = 140000\,{\text{dam}}$
Therefore, the distance between Mumbai to Delhi is 140000 dams. We always chose a greater unit for distance measurement when the distance between the two points is large. We cannot express such a large distance in decameter. Therefore, decameter cannot be preferred to express the distance between Mumbai and Delhi.
We know that, the distance between Mumbai and Delhi in meters would be,
$\left( {1400\,km} \right)\left( {\dfrac{{1000\,m}}{{1\,km}}} \right) = 1400000\,{\text{m}}$
That is 1.4 million meters. Therefore, we cannot express such a large distance in meters. Meter is can preferred to measure the length of the garden.If we express the distance between Mumbai and Delhi is centimeters, it would be,
$\left( {1400\,km} \right)\left( {\dfrac{{1000\,m}}{{1\,km}}} \right)\left( {\dfrac{{100\,cm}}{{1\,m}}} \right) = 140000000\,{\text{cm}}$
That is 140 million centimeters. Therefore, we cannot express such a large distance in centimeters. We can express the distance between Mumbai and Delhi in units of kilometers. Every distance measurement greater than 1000 meters, we always express it in kilometers.

So, the correct answer is option (D).

Note: There are larger units of measurement of distance than kilometer but are not usually used to express the distance. The kilometer is big enough to express the distance between any two points on the earth. We even measure the distance between two planets in kilometers if it’s less than one light year.