How to fugure increased value from CAP rate?!?

[Johann Kleisch]

Below is information I recently read on BP.  Can someone please explain how they got to the $338,824 increased value?

"You’re probably already familiar with the power of commercial real estate. For example, if you’re able to increase rents by $50 and decrease expenses by $50 per unit per month and you have a 24-unit apartment building like Brandon does, you’ve increased the income of the property by $28,800 per year.

Not that much, you say? It doesn’t seem like much. But if you assume that the capitalization rate is 8.5% for buildings like this in this area, then your tiny increase in income increased the value of the property by $338,824."

Thanks in advance!