Do you pronounce 敢吗？and 干嘛? the same? 敢吗？= Dare you?
干嘛? = What's up? What are you doing?

Do you pronounce them both the same and depending on the context, people can understand what you mean?
or
Do you pronounce them both a little bit differently which new beginners can hardly hear the difference?
敢吗？= Dare you? = gǎn ma?
干嘛? = What's up? What are you doing? = gàn má?