Mining at 0.1 GPS, how long to get one share? What does Grin difficulty mean?

Decided to try mining grin with Grinmint. I am CPU mining at almost 0.1 GPS. How long will it take to get 1 share at difficulty 1?

EDIT: Took about 15 minutes…

How is the difficulty convert into target in grin? Never understood this really well in bitcoin, even after reading Andreas book on this because difficulty bits in a block is in hexadecimal but when difficulty is given in decimal is confusing to me. I know that target = coefficient * 256**(exponent - 3) , where exponent is the first 2 hexadecimal digits of difficulty bits and the coefficient are the other hexadecimal digits (all this for bitcoin).

Can someone explain what difficulty in decimal means (in grin)?

Is that a confirmed transaction?

He was asked how long will it take to get 1 share, not how long will it take to find 1 block.

why 15 minutes?
I think is 42 /(0.1 * 60)= 7 minutes

the answer is in this thread, towards the end, i get some help with the math. it’s a bit of work