In the Kingdom, there are 7 dragons and 7 dragon slayers.
Each dragon has ($\text{index}\times10000$) hit points (i.e. $10,000\to70,000$).
Each dragon slayer does ($\text{index}\times1000$) damage (i.e. $1,000\to7,000$).
The local King asks the dragon slayers to slay all the dragons.
Each slay round consists of each dragon slayer each attacking a single dragon.
A dragon slayer cannot attack the same dragon again until he has attacked all remaining dragons.
Dragon slayers don't die.
The King figures it will take them at least $10$ slay rounds (hit point to damage ratio), and offers to pay $2,000,000-(\text{number of slay rounds taken}\times100,000)$.
Can it be done?