tcs - three companies are working independently and receiving the savings 20 30 40 if the companies work combinely what will be their net savings - skillgun

suppose total income is 100
so amount x is getting is 80
y is 70
z =60
total=210
but total money is 300
300-210=90
so they are getting 90 rs less
90 is 30% of 300 so they r getting 30% discount