6 is only the double of 3
3×2=6
Any number that's multiplied by 6 will be the double of any number multiplied by 3, or vice versa, any number multiplied by 3 will be half of any number multiplied by 6. This is because 6 is a multiple of 3.
Take for example:
850×6=5100 ⇔ 850×(3×2)=5100