an iron ore of 80 tonnes yielded 40 tonnes of metal which had 12 % of impurity what is the % of impurity in ore

a: 10%
b: 6%
c: 20%
d: 16%

• ans 6%
  12% in 40 tonnes means 24/5 tonnes
  if 40 tonnes has 24/5 impurity then 80 kg will also contain the same amount of imprity
  24/5 of 80 is 6%
• 8 years agoHelpfull: Yes(0) No(0)
• 12% of 40 tonnes = 4.8
  if 4.8 is the impurity in 40 tonnes then it will be same for 80 tonnes.
  x% of 80 tonnes = 4.8
  therefore, x=6%
• 7 years agoHelpfull: Yes(0) No(0)