So after 10 days, the stock price is $X+$3.
The next 10 days, the stock decreases by (10 days) times (45 cents a day) = -$4.50.
So the new price of the stock after 20 days is ($X+$3)-$4.50=$X-1.50. So the price is below the starting price.
Last 10 days the stock went up by (10 days) times (25 cents a day) = $2.5.
So the final total is ($X-$1.50)+$2.5=$X+$1
So the stock price went up one dollar over the whole month.