how long it takes to forge a block?
and what can I do to speed up the forging, a stronger CPU or something?
The time depends on the total amount of the balance of the forgers and your actual stake. The more is your effective balance the more are the probability to forge a block.
what if I can not solve this one, and just want to jump into next one, what can I do
If someone solved it you can just refresh the page and it loads the last problem generated.