//example-12.4
//page no-396
//given
//molecular weight of butdiene,isoprene,sulhur and carbon black are
MB=4*12+6*1
MI=68
MS=32
MC=12
//percentages of diiferent constituents in rubber
PB=27/MB
PI=51/MI
PS=16/MS
PC=6/MC
//percentage of coss linking
percent=PS/(PI+PB)*100
printf ("the percentage of cross linking is %d",percent)