Genel kültür soruları kolaydı.

Literally, genel kültür means general culture, but in everyday Turkish it often means general knowledge or trivia.

So genel kültür soruları is best understood as general knowledge questions or trivia questions, not questions about culture in a narrow sense.

Because this is a Turkish noun compound.

In Turkish, when one noun modifies another noun, the second noun usually takes a special ending: -(s)I.

So:

• soru = question
• genel kültür sorusu = a general knowledge question

When you make it plural:

• sorular = questions
• genel kültür soruları = general knowledge questions

That final -ı is part of the compound structure.

Not in this sentence.

That is a very common question, because soruları can look like an accusative form. But here it is not an object at all; it is the subject of the sentence.

Here, soruları is:

• soru = question
• -lar = plural
• -ı = the compound ending used in noun compounds

So the phrase means general knowledge questions, not the questions as a direct object.

kolaydı means was easy or were easy.

It is made from:

• kolay = easy
• -dı = past tense form of the copula, corresponding to was/were

So:

• kolay = easy
• kolaydı = was easy / were easy

Turkish often attaches this past to be meaning directly to the adjective or noun, instead of using a separate word like English was or were.

It is built into kolaydı.

English uses a separate verb:

• The questions were easy

Turkish often does not. Instead, the idea of to be is added as an ending:

• kolaydı = were easy / was easy

So there is no separate word corresponding exactly to English were.

Because Turkish adjectives do not agree with nouns in number the way English learners might expect.

In this sentence:

• soruları = questions
• kolaydı = were easy

You do not make the adjective plural. Turkish simply keeps kolay the same.

Also, with non-human plural subjects like questions, Turkish very commonly uses a singular-looking predicate form:

• Sorular kolaydı. = The questions were easy.

That is completely normal.

Because Turkish usually puts the predicate at the end of the sentence.

This sentence has:

• Genel kültür soruları = subject
• kolaydı = predicate

So the structure is basically:

• General knowledge questions
  • were easy

If kolay were directly describing the noun inside the noun phrase, it would come before the noun:

• kolay sorular = easy questions

But here the meaning is not easy questions as one noun phrase. It is a full statement: The general knowledge questions were easy.

The singular would be:

• Genel kültür sorusu kolaydı.

That means:

• The general knowledge question was easy.

Compare:

• sorusu = question
• soruları = questions

In the present tense, Turkish often has no overt word for is/are in simple sentences like this.

So you would usually say:

• Genel kültür soruları kolay.

That means:

• The general knowledge questions are easy.

Then the past tense adds the ending:

• Genel kültür soruları kolaydı. = The general knowledge questions were easy.

Not very naturally.

A literal breakdown would be something like:

• genel kültür = general culture / general knowledge
• soruları = its questions / questions of it

But natural English does not usually say general culture questions. The normal translation is:

• general knowledge questions
• trivia questions

So this is a good example where a natural translation is better than a strict word-for-word one.