GMAT Prep / Country's currency

well done.

the principal challenge of this problem is the sheer length of the wording in the problem statement: there are just a ton of words crammed into a rather small amount of space.

when you parse something like this, you should try your best to break it down into smaller parts:
add 2 percent of one's annual income to the average (arithmetic mean) of 100 units of country R's currency and 1 percent of one's annual income.
this is somewhat difficult to do on gmat problems, because you don't have a pre-printed piece of paper on which you can simply block things off and underline things; you'll have to write this stuff out on the yellow pad with which you're supplied at the exam.