If you've never played ranked before (like it's your first time), then winning 5 out of 10 should bring you to Silver 5. I remember winning 5/10 and getting Silver 4 I believe.
My looking at your games:
- You seem to only get fed off champions. If that doesn't occur you loose hard (because you're playing assassin/assassin-like champions). This can be solved by one thing, CSing better
In a 40 mins game you have 143 CS. You should of had around 250+.
In your 36 mins game between 200-230 and you have 118.
In your 32 mins game you have 116 and you should have 200.
I'm being honest, but if you can't improve those numbers I GUARANTEE you won't make it in the high silver. Here's a trick to improve:
Go into a custom game by yourself in Summoner's Rift and pick a champion with very unresponsive auto attack animations (slow) and that has 49 or less AD. I would recommend Vladimir (extremely low AD which is 47, close range autos, very slow animation). NO RUNES OR MASTERIES
--> Goal: CS 80 minions in 10 mins WITHOUT SPELLS. JUST AUTOS.
This will take you a few tries. But if you can do this, you'll start improving. I'm 100% sure about it.