If he is 4 now is in 10 years he will be 14 and if you multiply that by 2 you get 28 which means in 10 years Marie will be 28 so that means if you take away 10 the answer should be 18 but that isn't there but that's how I would work it out.
The type of decision that increases a nation's sphere of influence is called an Expansionist policy. This is a form of an aggressive and radical nationalism where expansionism is the main goal. Expansion in terms of military and economic context that caused a lot of major conflicts and colonization in history.
