Mining and Holding altcoin does not guarantee success. Also how will you ROI for a year if the prices of what you mined does not move at all? By the way what are the altcoins you mine that you are expecting to grow a 100% in a year? What process did you use in picking that altcoin to mine? Trading also won't insure 10% gain per month, life for the month of August - September 1 the prices only move from 560-580$ at what rate will you get the 10% gain in one month?
10% gain in altcoin markets is achievable for sure because the prices of altcoins fluctuate more than bitcoins price so earning profits with alt coins is faster than trading bitcoin itself, but make sure to trade only the trusted ones with a clean history.
But, from my experience making consistent profits from altcoin trading is always difficult but if we're lucky enough, we will get chances to double our capital in overnight through altcoin trading. But, with respect to available methods to double our bitcoins, altcoin must be very much effective one.