# Two ways of calculating real GDP: do they produce the same result?

My professor gave us two formulas for GDP for 2012 in 2010 dollars:

y = P1 (2010) * Q1 (2012) + P2 (2010) * Q2 (2012) ...

And:

y = x1 / (1 + inflation rate 2010 to 2012)

Where x1 is the nominal GDP for 2012. Do those formula produce the same result? If not, under what assumptions are they close to one another? Which one is used by governments to calculate GDP figures?

• I'm voting to close this question as off-topic because this seems like a simple homework problem with no effort shown. – Giskard Sep 12 '15 at 23:50
• @denesp It's actually not a homework problem. When I asked the professor, he didn't understand my question (English isn't his first language), so I thought I'd ask here. I tried searching google and couldn't find an answer; maybe I was searching the wrong thing. – sinθ Sep 12 '15 at 23:54
• I see. Looking up indeces, especially the Paasche price index may prove useful. en.wikipedia.org/wiki/List_of_price_index_formulas – Giskard Sep 13 '15 at 2:39