As per the information given in the question we have :
Cost of McDonald’s Big Mac in China = 2.44 Yuan
Cost of McDonald’s Big Mac in US Dollars = $ 4.20
Since Purchasing power parity holds good, the spot exchange rate between the Yuan and the US Dollar is
= 0.58 Yuan ( If rounded off to two decimal places )
Thus when the purchasing power parity holds good, 0.5810 Chinese yuan are required to purchase 1 U.S. dollar.