Firstly this is trading you make profit by buying at a lower price and selling at a higher price.
Secondly this doesn't happen daily the increase in price depends on the market status and the demand for the coin. If the demand is high the price will increase or else it reduces which might give you a loss.
What is important for you ?
You can double your btc but it's not a guarantee often price of btc increases but price of alt doesn't which means even if you bought at $10 a particular coin and the price of btc increased you will get a loss.
If you wanna take a risk invest in ltc I'm not giving any guarantee you will double your investment in 2 days but due to upcoming news there is a chance of price doubling.
What is the upcoming news regarding ltc?