[singaporesailer]

bro jerkface,
you can try comparing this way:
1RM--> VND = ??
1RM--> USD--> VND =??

Today's exchange rate is:
1RM = 6640VND
1RM = 0.31USD = 6570VND (1USD = 21200VND, so 0.31USD = 6570VND)

Which makes little sense to change twice (Rm> USD, USd> VND) but then again, it depends on how "generous" the goldsmiths are.
It will only make sense if 1RM gives you more USD than usual(likely the case if they like to clear their currency), or USD gives you more VND than usual, which you have to work out.

Apologies if above confuses rather than clarify