How can I check if the text of a button contains an element of an array?

You should not use the button's title to store data and compare it to a value.

Any time you write code who's logic depends on text displayed to the user you are paining yourself into a corner in terms of localization.

Using a numeric tag to index into an array of strings would be a much better idea.

Say you create an array of title strings.

Make each button's tag be 100 + the array index.

let startingTag = 100

@IBAction func qButton1(_ sender: UIButton) {
    guard let index = sender.tag where startingTag >= 100 else {
      return
    }
    //fetch your string from the array of button title strings you set up.
    let stringToFind = strings[index]
    if answers.contains(where: {$0 == stringToFind}) {
      //Found the current' buttons' string in answers
    } else {
      //string not found
    }

}