Use of Article + Plural

Question

I always find the use of article confusing. Also should "industry" be in plural? Which one is correct below?

1. I have worked in the banking and the engineering industry.
2. I have worked in the banking and engineering industry.
3. I have worked in banking and engineering industries.

Answer 1

Option 1 is incorrect because you are referring to two industries but using the singular "industry".

Option 2 implies banking & engineering are the same industry, which is incorrect.

Option 3 would be understandable but read better if it was written -

I have worked in the banking & engineering industries.

Answer 2

I don't think that banking can be described as an industry. Hence you might say:"I have worked in banking and in the engineering industry", but most people would say "I have worked in banking and engineering."