1. There is a black and white dog on the road.

2. There are a black and a white dog on the road.

3. There are a black and white dogs on the road.
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Are they grammatical? Which ones are grammatical?

2 answers

1 and 2 are correct. #3 is confusing. There is only one black dog and there are more than one white dogs? It's awkwardly worded.
1 and 2