7c div - 15.5% income return @ $0.45 per share, page-18

Aress says
"superk28 it's not quite so straight forward.
Let's say you had 50,000 AJA at the last divi. You would have received $2,500 in your bank account but will be required to pay tax on $5,145. If you're in the top tax bracket your divi would just about cover the tax bill."

Can someone explain this to me.

How do you pay tax on income that you are not involved with?

Are you paying tax on a interim and final divvy whilst only receiving 1 divvy?