Do Ukrainians speak Russian?
– Yes, all Ukrainians understand Russian. So if you h=are going to Ukraine with knowledge of Russian, you will be fine, don’t worry.
Now lets talk a little bit more.
Ukrainian and Russian languages are not the same. They are similar, because they belong to Slavic family, together with Polish, Czech, Slovenian and others. All people from Slavic countries somehow can get the idea of what they are talking about even without knowing the language.
But as Ukraine historically was a part of USSR, where official language was Russian, so everybody studied this language at school.
Nowadays in Ukraine official language is Ukrainian. And all official documents, schools are in Ukrainian. But still there are a lot of Russian media, Russian speaking people, and other language sources, so every Ukrainian, even if they never study this language, they start to know it in passive way. And as a result, everybody understand it.
Does everybody speak Russian? Well, still you can have situation when you ask people in Russian, but they answer you in Ukrainian. And it’s not because they are very patriotic. Just they don’t use it in life, and even if they understand it, it’s easier to answer in Ukrainian.