Company lying about salary or am I too daft to understand their offerings?

Browsing the local market for jobs and come across an advert that states the company is offering "from $50k salary". I applied as most of the offerings I've had are minimum wage so far. The next day I received an offer for an interview at the position I applied for. Cool I thought, might as well check it out. I do a bit more digging and find another advertisement that says they're hiring the same position at 15-17 an hour. Now I'm no math major but a quick use of the calculator pulls that closer to 30k than 50k. Are they lying about the actual salary to get more people to apply or is the "from" part of their offer just saying that's the maximum you can make at the company?

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