Sentence Correction

I like the explanation by rishab1988. I'd go with too. "three years" is time, so it should be less than three years.

You're giving an apples-to-oranges type of example. Comparing the numbers 12 and 15 isn't the same as saying 3 of something (i.e. years).

I guess the short of it is that units of time are not countable in the sense that apples, shoes, tires, and other visible discrete objects are.

rishab1988 wrote:*Less* is also used with numbers when they are on their own and with
expressions of measurement or time, e.g.:

His weight fell from 18 stone to *less* than 12.
Their marriage lasted *less* than two *years*.
Heath Square is *less* than four *miles* away from Dublin city centre

Numbers are countable right? You can say 1 ,2,3.But do you say 12 is fewer than 15?GMAT always says 12 is less than 15!

It is an apples to apples comparison for oxford dictionary has categorized numbers,time,distance,and units of measurement in the same category!.

Show me in what way is it different?

diebeatsthegmat, What's the source of this question?