Watercolor paints tend to be rather opaque.

I'm assuming this is a true or false question. I would say the answer is false. Watercolor tends to be more transparent then opaque yet it also depends on a few factors. If someone uses a lot it then it becomes more opaque. If they buy a specific brand it may also be more opaque. There are many factors that go into this question but most of the time water colors are more transparent than opaque.