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Which is correct?

Given 240 kph (240 kilometres per hour) = 149 mph (149 miles per hour)

How does one say this?

-240 kph equal 149 mph.
-240 kph equals 149 mph.
-240 kph is equal to 149 mph.
-240 kph are 149 mph.

Is 240 kph singular or plural (kilometre or kilometres)?
Or 240 kph is a seperate kind of thing?

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kilometers per hour is plural, of course miles per hour is also plural. – Elliott Frisch Feb 14 '14 at 20:58
Equals is correct, as is is equal to. There are some instances when one might use are, but that would be limited to when a quantity separates are from equal to, and would sound correct, but not necessarily be mathematically correct. – medica Feb 14 '14 at 21:09
up vote 0 down vote accepted

Correct ones are:

240kph equals 149mph; 240kph is equal to 149mph;

In 240kph, kilometres is plural.

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Even though the unit is "kilometers per hour," it's not really a "discrete" entity. You can't separate kilometers per hour from one another, and thus the unit acts as a "corporate" noun, where all the component "parts" belong to a larger unified whole. I would therefore opt for the singular:

240 kilometers per hour is equal to (or equals) 149 miles per hour.

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You may also see is equvalent to to emphasize that it's a unit conversion rather than an equation. – Bradd Szonye Feb 14 '14 at 21:52

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