40km per hour

[keannu]

Do you read this as "forty kilometers" plural or "forty kilometer" singular? Most unit notations seem to be treated as "plural", but are there any singular readings?

ma110)...This lifesaving robot first began patrolling Malibu's beaches in 2010. The robot can travel at almost 40km per hour...

[Route21]

As an NES, but not an English teacher:

I would normally pronounce it as "forty kilometres per hour" despite the abbreviation being singular.
In your context, "forty kilometre per hour" grates somewhat, unless used in the context of, say, "the 40 km per hour route vs the 80 km per hour route".

I'm happy to stand corrected if I'm breaking any grammar rules.

Regards
R21

[Grumpy]

"Forty kilometres per hour" is correct. Abbreviations are generally spelt the same, regardless of whether the full word is singular or plural.

[BobK]

I read it as 'Twenty-five miles per hour'.

b