How is 'letter' written in the code language? I. 'please write a letter' is written as '7218' 'received a Greek letter is written as '7513'. II. 'write in English please' is written as '2084' and 'a letter in Greek' is written as '5714'.

Data sufficiency questions are designed to check your ability to analyse & categorise information based on underlying concepts rather than calculations. So you should try to observe -  analyse and to find linkages between various statements rather soing lengthy calculations.