WHAT IS THE PARETO PRINCIPLE

Câu 42:What is the Pareto principle?A.If you work hard 80 percent of the time, you can relax for 20 percent.B.You need to do lots of work to increase sales by 20 percent.C.A few important things produce most of the results.D.Companies don’t need to hire more than 80 people.Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correctanswer to each of the questions from 43 to 50.Carbon dating can be used to estimate the age of any organic natural material; it has been usedsuccessfully in archeology to determine the age of ancient artifacts or fossils as well as in a variety of otherfields. The principleunderlyingthe use of carbon dating is that carbon is a part of all living things on Earth.Since a radioactive substance such as carbon-14 has a known half-life, the amount of carbon-14 remaining inan object can be used to date that object.Carbon-14 has a half-life of 5,570 years, which means that after that number of years, half of the carbon-14 atoms have decayed into nitrogen-14. It is the ratio of carbon-14 in that substance that indicates the age ofthe substance. If, for example, in a particular sample the amount of carbon-14 is roughly equivalent to theamount of nitrogen-14, this indicates that around half of the carbon-14 has decayed into nitrogen-14, and thesample is approximately 5,570 years old.Carbon dating cannot be used effectively in dating objects that are older than 80,000 years. When objectsare that old, much of the carbon-14 has already decayed into nitrogen-14, and the miniscule amount that isleft doesn’t provide a reliable measurement of age. In the case of older objects, other age-dating methods areavailable, methods which use radioactive atoms with longer half-lives than carbon has.