I am doing some research in mining and trying to do this but as you mentioning its very less 2.5$ in a day if we want to do near 25$ then what we have to do if you can explain if this is too much then between 10 to 15$ I am waiting for your reply
simple formula.
1 machine gets you $2.5 a day.
10 machines get you $25 a day.
subtract electricity costs, you have your daily profit (unless the $2.5/machine/day has that already calculated)
good tip but its costs too much and want some more then 2.5$ per machine is possible