Unless you have a specialized context, the subject is plural, since the gallons (think cans) of paint are what’s being sold. The only way I could see:

More than 1000 gallons of paint is sold

is to say:

More than 1000 gallons of paint is sold each day in each store.

Or something like that, but even then it would be a close call. So I’d go with are.

Unless you have a specialized context, the subject is plural, since the gallons (think cans) of paint are what’s being sold. The only way I could see:

More than 1000 gallons of paint is sold

is to say:

**For the main (paint manufacturing) plant, **more than 1000 gallons of paint is sold each day .

Or something like that, but even then it would be a close call, because paint is almost always sold as individual objects, cans of paint. So I’d go with are.

Unless you have a specialized context, the subject is plural, since the gallons (think "cans") of paint are what's being sold.
The only way I could see "More than 1000 gallons of paint is sold" is to say, "More than 1000 gallons of paint is sold each day in each store" or or something like that, but even then it would be a close call. So I'd go with "are".

Unless you have a specialized context, the subject is plural, since the gallons (think cans) of paint are what’s being sold. The only way I could see:

More than 1000 gallons of paint is sold

is to say:

More than 1000 gallons of paint is sold each day in each store.

Or something like that, but even then it would be a close call. So I’d go with are.