clc
//initialisation of variables
R= 0.082 //l-atm deg^-1 mole^-1
T= 25 //C
V= 85*10^-6 //l-atm g^-1
//CALCULATIONS
M= R*(273+T)/V
//RESULTS
printf ('average molecular weight of this polystrene = %.f g mole^-1',M)