singular/plural verbs

1 '100 metres is short / long / wide / tall' .
'100 miles is the distance between A and B'.
'60 years of prosperity was had under the Ly dynasty'.
An akwardkly constructed sentence probably better constructed as:
The population had 60 years of prosperity under the Li dynasty. Also, Is 60 years actually a dynasty?
I believe all the above sentences are correct.

2. '100 dollars were split evenly'. Correct.
100 one dollar notes were split evenly.

'100 metres of the city block were fully decorated in two days'.

'100 hours were spent on designing the first module'. correct

I think the first sentence requires 'was'.
I think the second sentence requires 'were'.
I think the third sentence requires 'was'. Incorrect

100 dollars = it

100 meters = it

60 years = it

"It" uses singular form of verb IN THOSE SENTENCES.


One hundred dollars WAS split several ways.

One hundred meters IS a long way to walk.

Sixty years IS a very long time to wait.

Thanks, guys.