Question

Which of these could NOT be a measurement of speed? A. 5 km/h B. 3 mm/s C. 2.5 days/mi D. 15,600 cm/min

Answer 1

Answer:

C. 2.5 days/mi

Explanation:

Speed is defined as the distance covered by an object divided by the time taken to cover that distance:

$v=\frac{S}{t}$

where

S is the distance covered

t is the time taken

At the numerator of the fraction, we have distance, which is a lenght. Lenght is measured in different possible units: meters (m), kilometer (km), mile (mi), centimeter (cm)...

At the denominator, we have a time, which can be measured in seconds (s), minutes (min), hours (h), days..

According to this, we can see that option

C. 2.5 days/mi

cannot represent a speed. In fact, at the numeratore we have days (which is a measure of time), while at the denominator we have mile (which is a measure of length), so in this fraction distance and time are inverted, therefore this cannot be a measurement of a speed.

Answer 2

The answer is C 2.5 days/mi