This one has been driving me crazy too.
Now it's a huge trouble to do all the work, so I'm just going to ask you guys if you would approach it the same way I did. Which is for example Euro, I would take 1 and divide by 1.52 and 1.64 and see the difference of that. Do it for all currencies and see which number is the smallest?
Or do you just subtract the 1.64 and 1.52? (Seems too easy)
I've been out of school too long to remember proportional change
By the way, this is not homework or anything. It's prep for numerical tests - you do them when you apply for a banking job. And you get 1 minute for each problem.